So working on a Min Gas scenario, which for GUE (unlikely sidemounters, I know) is 1200 litres for a 30m dive, or 50bar in twinset, based on 2 divers breathing 30lpm. What is the correct protocol for having the gas available in Sidemount? 50 bar min in each cylinder (assuming 12l)? Although this is the same amount of gas, when all gas is accessible you can have one diver breathing 25lpm and the other 35lpm and it is balanced out. With isolated cylinders you lose this benefit, so do you push up the min gas in each cylinder or leave as is?
The hijack seems more fun... If you know one diver has an especially high SAC rate, you'd use that as the basis for your rock bottom calculation and that would decide your reserve for you, surely? If you're positing that someone might breathe even more than the breathing-more-than-expected amount, you can't really assume that'll be evened out by someone else breathing a little less in the event of diving doubles, so your rock bottom calculations are blown and it's all gone horribly wrong anyway. The whole point of doubling usual SAC rates when working out rock bottom is that it's a worst-case scenario - if you believe a team-mate will breathe faster than that then I guess your options are (a) plan reserves accordingly or (b) find a team-mate who keeps better control of their breathing when it all goes to custard
I tend to work out what I need for the dive, including contingencies and rock bottom, and then just carry a lot more than that. Seems to work.
GUE use 30lpm as the stressed SAC rate and 20lpm as normal. With min gas based on the stressed SAC. Now stressed SAC rates can massively spike, which is an issue in either manifold or independent tanks. I just wondered what the SOP is for sidemount.