[annapurna]

I'd also worry about forming an air bubble during ascent which then is ejected out of the annulus of the M6 and into your system. If I remember correctly there's a form of embolism that is similar to that, pneumothorax if I've got the name correct.

I'd suggest that you constrain yourself to single tank dives with no decompression allowed. Go ahead and include safety stops as needed but I wouldn't do anything that required you to decompress. Can you tell I used to do quite a bit of diving years ago? I'd imagine that the diffusion into and out of the fluid that flows into the M6 will be somewhat poor, that's why I'm suggesting shallow and short dives and watching your surface intervals to limit build-up so you never need decompression.