Well that sounds like torment 3 at least but it's HC and it's a monk, I only have experience on ubers as a CMWW prepatch and a DH post patch using companion and sentries and mostly just staying the fuck away. Ubers sound really fucking scary on HC so I don't know. On softcore with those stats I'd go straight torment 6 but it's probably very risky.
Difference in drop rate isn't as big as it used to be though, torment 1 is 25 and torment 6 is 50%, so it's not like 10% to 100% like it was pre 2.0, so even if you do one or even 2 torments lower than what you could handle, you only lose 10% chance. I'd say start at 2 or 3, do all 3 fights(they're vastly different in difficulties imo) and see how it works out.
Also for safety I'd probably run the pet skill, it tanks shit so if you're solo it'll probably distact one of the ubers, reducing potential damage a ton. The one that heals you for full hp seems to be the obvious choice but it does disapear for a long time if you use it, so maybe something like the earth one instead. Or you find other people to go, then it should be safer, even though it also means the fights will last a fuckton longer.