This guide is to help anyone who wants to know what the best sticker positions for guns are.
Katowice 2014/2015, crown, howling dawns, and other stickers use these positions to calculate how much that sticker (or stickers) adds to the gun, or just to know how visible it is.
Rifles


AK-47
1st best - on the wood, leftmost position
2nd best - back of body, rightmost position
3rd best - middle right of body, second to rightmost position
4th best - middle left of body, second to leftmost position

SG553
1st best - above the mag, leftmost position
2nd best - middle of body, second to rightmost and leftmost positions
3rd best - above trigger, rigthmost position
4th best - on the scope, the top position

Galil AR
1st best - back of body, second to rightmost position
2nd best - above mag, second to leftmost position
3rd best - the barrel, leftmost position
4th best - the stock, rightmost position

M4A4
1st best - above the mag, leftmost position
2nd best - above the 1st best, second to leftmost position
3rd best - back of the body, second to rightmost position
4th best - the stock, rightmost position

M4A1-S
1st best - above the mag, second to leftmost position
2nd best - middle of body, second to rightmost position
3rd best - back of body, rightmost position
4th best - barrel, leftmost position

AUG
1st best - above the handle, second to leftmost position
2nd best - above the trigger, leftmost position
3rd best - above the mag, second to rightmost position
4th best - the stock, rightmost position

FAMAS
1st best - front of body, leftmost position
2nd best - middle left of body, second to leftmost position
3rd best - the biggest spot, rightmost position
4th best - middle right of body, second to rightmost position

AWP
1st best - on the scope, topmost position
2nd best - below the scope, leftmost position on body
3rd best - middle of body, second to both leftmost and rightmost positions on body
4th best - the stock, rightmost position

Scout/SSG08
1st best - above the mag, second to leftmost position
2nd best - front of body, leftmost position
3rd best - middle right of body, second to rightmost position
4th best - back of body, rightmost position

SCAR-20
1st best - above the mag, bottom left position
2nd best - below scope, the top left position
3rd best - middle of body, second to rightmost position
4th best - on the stock, rightmost position

G3SG1
1st best- in front of mag, leftmost position
2nd best - middle of stock, second to rightmost position
3rd best - on the scope, top position
4th best - above trigger, second from leftmost position on body
5th best - back of stock, rightmost position

P90
1st best - the big spot, second to leftmost position
2nd best - above grip, leftmost position
3rd best - middle of stock, second to rightmost position
4th best - back of stock, rightmost position

MP7
1st best - middle of body, second to leftmost and rightmost position
2nd best - above mag, front of body position
3rd best - very back of body, rightmost position
4th best - on the handle, bottom position

MP5
1st best - back of body, rightmost position
2nd best - middle right of body, second to rightmost position
3rd best - middle left of body, second to leftmost position
4th best - front of body, leftmost position

PP-Bizon
1st best - back of body, rightmost position
2nd best - above mag, leftmost on position
3rd best - middle of body, second to the rightmost and leftmost positions on body
4th best - on the mag, lowest position

MP9
1st best - back of body, rightmost position
2nd best - above mag, middle of body position
3rd best - front of body, leftmost position
4th best - on the handle, bottom position

UMP-45
1st best - front of body, leftmost position
2nd best - middle left of body, second to leftmost position
3rd best - middle right of body, second to rightmost position
4th best - back of body, rightmost position

MAC-10
1st best - back of body, rightmost position
2nd best - above mag, middle of body position
3rd best - front of body, leftmost position
4th best - on the handle, bottom position

XM1014
1st best - back of body, rightmost position
2nd best - middle of the body, second to rightmost position
3rd best - middle left of body, second to leftmost position
4th best - on grip, leftmost position

MAG-7
1st best - above the mag, second to rightmost position
2nd best - back of body, rightmost position
3rd best - above the trigger, second to leftmost position
4th best - front of body, leftmost position

Sawed-Off
1st best - back of body, rightmost position
2nd best - middle of body, second to rightmost position
3rd best -front of body, second to leftmost position
4th best - the pump, leftmost position

Nova
1st best - above the trigger, rightmost position
2nd best - middle of body, second to leftmost position
3rd best - front of body, leftmost position
4th best - the back, unseeable in screenshot

Negev
1st best - back of body, rightmost position
2nd best - above the trigger, second to leftmost position
3rd best - on the mag, bottom position
4th best - front of body, leftmost position

M249
1st best - above the grip, second to rightmost position
2nd best - above the trigger, leftmost position
3rd best - next to stock, rightmost position
4th best - on the mag, unseeable in screenshot

Desert Eagle
1st best - above mag, top right position
2nd best - on the tip, leftmost position
3rd best - middle of top, second to rightmost and leftmost positions
4th best - on grip, bottom right position

R8 Revolver
1st best - next to cylinder, second to leftmost position
2nd best - on the cylinder in screenshot, second to rightmost position
3rd best - on the tip, leftmost position
4th best - on the grip, bottom right position
5th best - on the other side of the cylinder, unseeable from screenshot

Tec-9
1st best - above grip, top right position
2nd best - middle of body, second to leftmost position
3rd best - above the mag, leftmost position
4th best - back of grip, unseeable on screenshot

Five-SeveN
1st best - above mag, top right position
2nd best - on the tip, leftmost position
3rd best - middle of top, second to rightmost and leftmost positions
4th best - on grip, bottom right position

CZ-75 Auto
1st best - above grip, top right position
2nd best - on the tip, leftmost position
3rd best - middle of top, second to rightmost and leftmost positions
4th best - on grip, bottom right position

Dual Berettas
1st best - right hand's pistol barrel
2nd best - left hand's pistol above mag
3rd best - left hand's pistol barrel
4th best - right hand pistol's mag

P250
1st best - above mag, top right position
2nd best - on the tip, leftmost position
3rd best - middle of top, second to rightmost and leftmost positions
4th best - on grip, bottom right position

Glock-18
1st best - above mag, top right position
2nd best - on the tip, leftmost position
3rd best - middle of top, second to rightmost and leftmost positions
4th best - on grip, bottom right position

USP-S
1st best - above mag, top right position
2nd best - on the tip, leftmost position
3rd best - middle of top, second to rightmost and leftmost positions
4th best - on grip, bottom right position

P2000
1st best - above mag, top right position
2nd best - on the tip, leftmost position
3rd best - middle of top, second to rightmost and leftmost positions
4th best - on grip, bottom right position

Some of these positions might be wrong for the more 'niche' guns, so please put in the comments of this guide what is wrong and why it is wrong without being all toxic so I can fix it as soon as possible.