I'd prefer to be the Phantom Corps since they have a cooler name, and I don't particularly prefer the shades blue of the rival guns, too pale for my tastes and I don't like the color red as much. I only have a team Red apollo and Zeus with a red face mask however since thats all they had at any stores I went to, but I will probably get a Hera soon.
You could try to make a homemade version of a Big Blast release mechanism. A descent hardware store should provide the proper PVC and other parts. If that would end up being a more costly solution, you could always just save money to buy the mjvo-3 valves.
Aside from that, I suggest just walking up and down the aisles of your local hardware stores(assuming you have more than one) and try to get ideas from that.