Tornadowbow help

Hello everyone. As some of you know, I thrifted a Koosh Vortex Tornado a while back, and now I want to turn it into a Tornadobow. This thread is intended to request help and ask a few questions about doing this because 1: I have no money to spend, and 2: I have no power tools. So, lets ask some questions. Maniacal coyote, maybe you can use this thread too.
1: Plunger tube? I currently have the tube part of a squirt gun (the long tube kind, begs to be made into a plunger tube) taped into my tornado. I dod this because I didn't have anything else to use, and it fit right. I can cut the plunger head off of the other piece, it has a perfect seal.
2. Catch? I have access to most hand tools outside of a rasp and rat tail file, and yes aeromech, I saw your youtube video. That probably will work, but I need polycarb or pvc sheets, which I would have to buy online unless I can find it at ace.
3. Spring? Ace spring could work, other than that I don't have many options. Maybe buying cheap ones online?
Please help. I also have as raw materials: Tapes of various kinds, 1/2 inch pvc and cpvc, a local ace hardware, milk jugs(?) wood, metal bar, junk in general.
Sidenote: the ring launcher is completely functional outside of the shell. It just looks HIGHLY phallic.