My mum always said tummy's were great because we didn't get the wind and we slept soundly!! Saying this, of course SIDS recommends no tummies. What I would suggest if it really works for you, is getting a breathing monitor (we have one, I love it) and it sensors if bub stops breathing. And as long as there's no other risk factors, and you watch bub, it should be ok.
Mind you i don't want to give advice that goes against recommendations, so let me put it this way...that is what I would do! xoxoo