I've been diving and shooting with a rebreather since 2007. The best advice I can give you for your bail-out is to rig them in a side mount harness, so the tops of the bottles are pulled up, instead of hanging down low. Take a look at the photo examples on the bottom of this page: http://store.addheli...mount_c_19.html
The trick is to have the lower portion of your stage bottle clipped off low on your body - preferable on your rear-end. The top of the bottle needs to be pulled up into your armpit. This is generally done with a bungee of some sort which is fastened to the backplate or harness behind you. The bungee is then pulled down and clipped to the top of the tank in some fashion, to pull it up and out of the way.
There are tons of different ways to do this, and divers will spend years perfecting the technique. I've been side mounting bailout for 7 years, and I still tweak the design when I see new ideas.
The Dive Rite Nomad is a great harness, and the air cell allows for good trim while on a rebreather. The side mount tank bungees Dive Rite offers are a bit weak though - they tend to fray after about 1 year of use. Hollis just released their SMS75, which has a really well designed bungee system, and Halcyon will be introducing something similar soon.