LoL... Solo'd all mids but Cactus Jack at 32-34, all pretty easy just have high hp. Just make sure you have buffs and cures and the nm's are insanely easy regardless.
Edit: Dots also go super long way... and jeez cant believe how many people are unable to solo these nm's o.O Was 30 conj when the NM's first came out and defeated 5 random ones np... ranked up a bit from leves... did almost all the rest, rinse and repeat for last ones... Think I'm missing what's so hard about the nm's LoL Duo'd my last NM of the new batch at 35 with another 35 (Jack, 1k needles gets split to 500 ^^)