36SD Heroic mixed with Onyx armor HP(Glacial is also okay), upg weapon with high DD 40 or more with abs(without abs it's too hard to solo). The only class I tried can solo in WH without abs and upg is Priest with 7s(prob rumir but never play it). I use Staff 6x Magic Attack, 4x DD, 8/10 abs hp mp. I hit like 70-80k(well ofc boss drops acc and costume stuffs helps) with Judgement that has only 3 secs cd. Staff Mastery will convert 30% from your total damage dealt into Mana, also that abs 8/10 hp mp makes you immortal along with Marea Grace always active, don't forget Soul Mediation, MB and Obligation(let alone Perfect Heal).

Other class I tried can solo in WH is Predator but I use upg(no abs but Heal Trap helps you survive).

I have no idea about other class, I tried Guard but without abs it was too hard soloing there, never tried rumir but I've seen a lot of them managed to solo mirror and WH.

For soloing it is also important to give delay between your buff(maybe like 2 mins duration each buff), so you won't end up die because rebuffing all buff in one go.