Someones got that posted in here somewhere but when my OL was 40 i had a Dark Screamer with focus +3 dagger and i used Theca set and a Demon set and it worked for me then for B grade i used a Avadon Robe set. I think everyones pretty much gonna tell you to go Full Plate set for armor though and if you want to use light armor then get a Plated Leather set becuase that's the usual player base recomendations on c grade and for the robes i think they'll say Karmian.
B grade armors BW is only one they will recommend and as far as A grade goes i'm not gonna suggest anything cuz i'm using common Tallum light on my OL and usually grind with fists when i actually play him and i'm not on 1 of my others.