hanyuduck2005:
Are we alowed to use an backplate/ wing for the Divemasters certification???
Nothing I've seen in PADI's standards prevent it, but I don't pretend to have exhaustive knowledge of their system.
My DM qualification dives are the only dives I've had so far where the DIR rig wasn't "optimal", as they say. I dive an older plate and weighted single tank adapter.
In the pool without a dry suit I was overweighted with just the plate and adapter. No problem really, except during the "genie float". With the extra air I had in the wing the rig wouldn't hold me upright, instead it pushed me forward and to the left. Once I quit fighting it by sculling with my hands I was all right, just looked a bit goofy hovering in the middle of the water column tilted several degrees off centre like a spinning top.
The instructor didn't get the breathing-the-long-hose-bungeed backup-reg idea at all. I thought I had explained it to him (my buddies got the idea quickly) but he insisted that we had to carry a snorkel on our mask straps at all times. Long hoses don't deploy well over a snorkel during an OOA drill. Actually, they suck.
If I had it to do over again, and assuming I wasn't feeling ornery, I'd have borrowed a jacket BC for the course, scrounged a snorkel keeper, and either swapped the seven foot hose for a 40 incher, or gone completely tourist with a clipped off octopus and conventional primary. Then run screaming back to my backplate as soon as the course was over.
Talk to your instructor. It will be his or her translation of the standards that governs how you dive. Dive what works for the job.