There are thousands of threads about this topic spread throughout forums.

I concluded the answer is much more obvious than merits the discussions.

As a base I used the following spreadsheet (credits to the author are due):
https://docs.google.com/spreadsheets/d/1UA8wbaJyU7psie8476dIS2WjJ8AjUijTGVtC36EtOYo/edit?usp=sharing



Basically when min/maxing (no fashion souls consideration, sorry) you want to get the best defense out of the minimum weight.

For that purpose, without question, the best set is the Transparant Aurous Set .

Allow me to explain:

Every piece of the set increases the equipment load of your character.
Head by 0.8, chest by 1.2, gloves by 0.8, legs by 1.2
This bonus can be reinterpreted more easily as reduction to the weight of the armor itself, meaning the head piece instead of weighting 1.2 actually weights 0.4, 3.2 to 1.9 weight conversion for the chest, 1.2 to 0.4 for the gloves, 2 to 0.7 for the legs. A simplification not 100% accurate

this has the following implications on the total defenses to weight ratio:
Helm of Aurous+5 (original weight) Total Def/Weight 160.83
Helm of Aurous+5 (modified weight) Total Def/Weight 482.5
Armor of Aurous (original weight)+5 Total Def/Weight 160.63
Armor of Aurous (modified weight)+5 Total Def/Weight 270.53
Gauntlets of Aurous (original weight)+5 Total Def/Weight 160.83
Gauntlets of Aurous (modified weight)+5 Total Def/Weight 482.5
Leggings of Aurous (original weight)+5 Total Def/Weight 160.5
Leggings of Aurous (modified weight)+5 Total Def/Weight 458.57


That said, the set has 0 poise, a very important factor to take into account.
With that taken into consideration, another min/max strategy can be traced based on your aimed encumberance %.

Having the Invisible Auros set crazy ratio in mind but looking for a balance in poise, I suggest changing the helmet to the Vengarl's Helm for the same reasons of the auros set. it gives a + 2 vit bonus which means a 3 whooping weight difference if your original character vit is at 28. with this exact paramater in consideration, the helmet weights 3.8 instead of 6.8 (the vit weight gains are different based on your original vitality, 28 to 30 is the sweet spot).
this gives you a Total Def/Weight of 142, 12 poise for a Poise/Weight ratio of 3.16.
Another viable option is the Velstadt's Helm which also gives you +2 stats and has arguiably the best def/weight with poise.
The Penal Mask is not the best option when compared to the 2 helmets above, but can be viable as well.


The chest piece is where you are going to have the best choice for choosing the piece that best fits the total encumberance you are aiming for. considering poise + def/weight ratio, i suggest Velstadt's Armor at 15.2 weight, Alonne Captain Armor at 15.6 weight and 38 poise (with added benefit of fire resistance bonus) or for the lighter options Gyrm at 26 poise and 12 weight, Alva Armor at 15 poise and 8.8 weight.


a last note: i use alva set + Vengarl's helm because of Fashion ;)

Thanks for reading,

Boomaye