Hi !
Concerning dry suit as a buoyancy device : not a problem ! It's been done for years. Although I was dry suit trained relatively recently (a bit more than 10 years ago), I was taught both way (i.e using my dry suit as a main buoyancy source or my BCD, with just enough air in the suit to prevent squeezing).
My concern would be the lack of redundant buoyancy, as already stated. A SMB might help, as already stated (once again) but I would STRONGLY advise that you get someone to teach you that skill. Unproper use of an SMB as an alternative buoyancy device can be disastrous : meaning rocketing to the surface, with all the unpleasant consequences.
Over the years, I've seen (then helped) fellow divers who were complacent while using SMB, that I'm "almost" scared of the device now.
Concerning dry suit as a buoyancy device : not a problem ! It's been done for years. Although I was dry suit trained relatively recently (a bit more than 10 years ago), I was taught both way (i.e using my dry suit as a main buoyancy source or my BCD, with just enough air in the suit to prevent squeezing).
My concern would be the lack of redundant buoyancy, as already stated. A SMB might help, as already stated (once again) but I would STRONGLY advise that you get someone to teach you that skill. Unproper use of an SMB as an alternative buoyancy device can be disastrous : meaning rocketing to the surface, with all the unpleasant consequences.
Over the years, I've seen (then helped) fellow divers who were complacent while using SMB, that I'm "almost" scared of the device now.