Yea, I build them. Sure, you could use any trigger release you like. Look into a thumb ring (mongolian) and using it properly. Make a thumb ring from horn, bone, even doggie rawhide strips. Paleo planet, look for a guy named Fiddler, he explains making and use, has tutorials elsewhere.

If your draw is 31 you should have gotten a 31" draw. If it is marked 30" it wasn't tested for 31.

I don't shoot wheel bows, carbon, alum and use real blackpowder. If you get into longbows, self bows you may want to remain "purist" 3 Rivers Archery has wood arrows. I make arrows from river cane. I also do atlatls, bet you would get a kick out of them too. Don't forget an armguard, arrows can and do shatter with pieces going thru your forearm.