Extremely easy solo of any MR on any level as blu, especially with npc, add a healer buddy and it's beyond a joke.
BLU/DNC
Bludgeon, Head Butt, Grand Slam, Cocoon, metallic body are your basic requirements. Personally beyond that, I go with sopo/breeze/poison breath/sheep song for the traits. (Mostly because I do it for npc, and clear mind is invaluable).
Each MR is an extremely simple process:
Buff. Gather all strays. Kill them with Grand Slam. Use a sleep in between grand slams if necessary, but 2 gs should kill them all 90% of the time.
Heal to full. Get close to mr, lock target. Engage, watch for swing action. The instant your swing starts, hit head butt. This prevents the seed they *always* open with. Then just alternate bludgeon/head butt (eventually you'll get used to the timing and be able to stop a lot of the seeds.) Start mixing grand slam in when there's 3 adds out.
It's really that simple. It's extremely easy to stay alive with waltzes, I actually use flat blade to stop seeds sometimes even. The MR's really don't have a lot of health, and like I said 2 rounds of grand slams should kill off the adds np.
I stopped trying to solo the actual enm's tho (well I never tried 50), mea/dem/holla just owned me before I could really make any worthwhile progress.