I might be missing your intent again, but I think you might be underestimating the impact that keeping your cylinder connected will have.
PIC
When you compress that cylinder down to (edit lol: umm "Rooster") your firing mechanism, you will have ~60psi (or less if you regulate it further down) holding it in that position until you go to fire it. When you fire it, yes the latex tubing will pull it out, but it is forced to exhaust the entire contents of that piston chamber either back through the solenoid valve (worst case) or through a seperately actuated solenoid valve Tee'd in at the cylinder. Either way, you are limited to an 1/8" valve size, which means it takes a non-zero amount of time to exhaust it.
Essentially, your piston will act as an air damper for your firing mechanism. This is why many people considering pneumatics as a way to store energy in a spring (or otherwise) are looking to use a "trigger" that will allow the latex tubing to fire without the cylinder slowing it down.
Thanks,
Steven