I would like to hit the armor cap asap on a 2H char with Dragonplate, preferably getting the minimum # of alch/enchant perks. So what would be the minimum +%BS needed to improve Dragonplate to 576 AR with Perks?
To my calculations....
5/5 Jug : 100%
1/1 Fitted : 25%
1/1 Full Set : 25%
= +150% AR
572 / 2.5 = 228.8 AR needed before perks

according to elderscrolls.wikia (apparently I cant post links) Dragonplate (without the shield) has a base armor of 104.

I tried to understand this page from another wiki "uesp.net /w/ index.php? title= Skyrim: Armor&diff =next&oldid =811708" specfically addressing my question, but I got very confused.

I just want to know what level of +BS% total I need when improving the dragonplate in order to hit the armor cap, assuming 100 Smith and 100 Heavy Armor.

From what I read, you'll need an effective skill of 140. So a +40% potion should do the trick.

But don't you also get an armor bonus simply for having high heavy armor skill, in addition to those perks? If so, you may not need even that.