Rcmt is the same course as cmt (medic phase 2), only done as as a fully trained (usually infantry) soldier, and thus can be quite hard to get on.
That said, whilst doing the same course you get a bit of credit for being fully trained, ie get to wear dpm, instead of lightweights, no room inspections, get treated like adults, don't have to share rooms, no guard. Still the same course, but less phase 2 bullshit. But for this you have to act as permanent class seniors.
Usually about 10 RCMT's to 50 phase 2 CMT's.
rma is just the old version of rcmt.
and the course is 20 weeks long, with weekends and summer/ christmas leave.