its been a few years since I've used a co2, I gave up on them since each cartridge ran at least a buck and I don't race. it seem like such a waste to toss a cartridge after each use. I had a flat a month ago and used a friends mini...I was really impressed. high volume mode filled the tire and switch to high pressure and bring it up to 100+ psi.
http://www.cambriabike.com/shopexd.asp?ID=10278