As far as I know the res cap is around 32k.
Is it wise to go a few thousand more than that as most classes have access to some resistance lowering abilities either actively or passively.
I was thinking maybe 35kish would be enough?
I am thinking of using Chudan, all impen trait on my gear and also Armor master set with Boundless armor on my magicka sorcerer.
All of this together ought to cap at around 35k.