I mean if you're wanting best GRuin force numbers probably some weird like 12/5 Warlock/Wizard with T5 AM
"Sustainable":
3% Knight's Strike (T4 EK)
5% Primal Shrine buff
15% Scion of Feywild
16% Fili
30% Spellpower feats (4x)
30% crit damage from TS C4
35% gear (IoD 20/10/5% easiest)
60% MoK 30 stacks
Temporary:
20% Wellspring
25% NR clicky
100% Arcane Supremacy
339% extra, plus 100% base, = 5.39x force crits.
Including metas and clickies (AB, reaper boost, Wellspring, Tide, etc) you're probs idk 1500 SP, so 16k x 5.39 = 86k force damage before debuffs? Timestop, Vuln, etc for screenshot time?
Can't say I'd recommend it lol. I had a GRuin build back when Offhand Versatility had an auto-crit proc, and it was ok on a good day (could pump a fair bit if I didn't care about SP but that's rarely true).
Tainted Scholar really gets +60% spell crit, huh. It seems like it'd be fairly easy for them to get above 100%; there's no triple damage contingency like with doubleshot, is there?
It's not a chance for an increased multiplier (like DS is), it's a direct multiplier - if you have +184% spell crit damage you just multiply your base damage by 3.84x on a crit (since they start with +100%, or 2x). AFAIK there's no cap to it (Arcane Supremacy + Wellspring is great for snapshotting auras on PM, for instance).