CO2 or HPA small bottles?

[Babalui]

Hi,
There was some discussion among my gang when I brought up my MR1 with CO2 adapter. Many things are unclear to us and I was wandering if you could help me to clear up few things...

I have "classic" CO2 adapter like this one:


This system has a drawback that changing the cartridge is rather slow, although faster then on Piranha USP. Major concern is that in order to be silent, I have to activate it (and test it) before the game. In cases when I didn't shoot any balls or quite few of them, almost full cartridge is wasted.

So, I have following questions:
- is there any adapter that enables faster cartridge reloading? I thing I saw one that does not require screwing, but some sort of clamp?
- what's the smallest refillable CO2 bottle and its price?
- what's the smallest HPA bottle and its price?
- what are the dimensions of above bottles? any choice of slimmer bottle?

My intent is to use it for scenario games only

Thanks in advance