[NotDeadYet]

What Broady says. You should get a chance to play with different set ups.

I prefer a side slung bottle, I like access to the valves/regs, I like it being tucked out the way from anyone grabbing it and I like being able to take it off/hand it off if needs be. Downside is with a normal stab jacket then it isn't particularly convenient as the d-rings are usually fixed and in the wrong place. Ideally a webbing harness is best.

Worn on the back there are downsides to the way it's rigged. You can clip off the 2nd stage like a pony reg in which case it can be mistaken for a pony reg. You can invert it and shut the valve off in which case if it gets mistaken for a pony reg then someone is going to get a reg which will go dead after one breath. You could bungee the hose against the cylinder out the way and pull it out when you need it but once it's out you can't put it away on your own.

If you want to borrow a stage and/or twinset for the SOM trip let me know, I've got spares. As Clare says, flog the pony, buy another cylinder and set up twins. With a single cylinder the time advantage of carrying a deco stage is minimal (especially if restricted to EAN50 or something post course), better off spending the money on twins rather than a stage which isn't gaining you much.

Cheers,

Stuart