I've only had a limited experience so far Vic and so far I've used mostly Alumilite and last night tried FC6600 to see what the difference is. I've used a block mould and resin saver moulds and have had good results with the resin saver and pressurise them to 60psi (4bar) without any problems, just make sure the plugs are in properly. The mould shouldn't contain any gas and therefore won't be able to be compressed and if the plugs are in properly you'll be fine.
On the pressure side of it...
pressurising to 1 bar (15psi)(30' in the water) a bubble will be halved in size
pressurising to 3 bar (45psi)(90' in the water) a bubble will be quarter the size
pressurising to 7 bar (105psi)(210' in the water) a bubble would be an eighth the size
The pressures / depths are roughly right but gives you an idea and the biggest change is down to 15psi. If you decide to stick at 40psi with Alumilite then I think you will be fine as it looks like the bubbles mostly disappear on their own anyway. Yesterday I put the cup of mixed resin in the vacuum chamber before pouring it and the majority of bubbles had gone although more are added on pouring of course.
I look forward to seeing your results. 
