I did J11 on all settings (Battle Settings Multiplier = 75.76x) and managed to defeat the final wave with 2x Grade 33 gems. It is definitely possible to do it with 1 G33 gem, probably possible to do it with 1G32 gem. The final waves had an armour of > 100 million, but my gems had max damage of >100 million with multipliers of >1000.
I took a screenshot of the endurance results (138.42x) however I don’t know how to upload it here. I will save it until someone tells me how to (if its possible).
My final score was 36,659,403