Something like this with a 3.5 oz aluminum tank with on/off:
When I had it set up before, I had the ASA facing forward with one of those 30 gram tanks with on/off from RAM. It looked pretty star-wars with the tank pointing forward.
I can say that this is one of the most reliable, best shooting stock class semis I have ever used.
Had a pipe tip on it for a while and it was easier to point, but can't say it shot any better....or worse beacuse of it.