Hey,

from what I know, plate is great for arena (due to 3:1 meele/caster ratio) and chain and probably even scales beat the plate in catas due to the higher number of caster mobs.
I wonder which type well monsters have. Does this depend on the item you've thrown in the well? Could it even make sense to have a robe and a plate because it's possible to predict the dam type?

you can not predict type

so stick to 1 armor (preferably heavy)

Imo, go with a scale or leather to give you some defense on both which will allow you to complete more wells if your heals are mediocre

i assume hybrid?

if so i personally dont care on armor if ur hybrid

i welled 100% perfect w/ my pally b4 i passed recently w/ a plate armor w/ str

Also depends on other items...
____________

Either way... scale/chain/plate are better than a robe...
I welled effectively with my Monk (even @ level 55 being hybrid)... so with this said... Plate/Scale will give you better defense... note... my monk armor is level 35 and welling @ 55