I am a huge fan of using the microwave for extractions. Matter o' fact, here are two teks that I have published on the Nexus which are centralized around microwave use:
MAD tek ; and
MMMAD tek.
However, in those teks, the microwave was used for short acid cooks, not for evaporation. My instinct tells me that the microwave for evap could be a risky route, with possibility of easily boiling over and overflows / accidentally fries the DMT.
But, we learn from experimentation.
I would personally try something with the candle warmer.
Sometimes it's good for a change. Other times it isn't.