I used Chicago Screws to attach mine and absolutely love it. I started with Velcro to get it placed and then marked it and went with the screws. I’ve seen snaps used too and they work well.
It’s a long process from start to finish but in the end, it’s all worth it when you suit up. Good luck on the rest of your build and I look forward to following along.
This is the exact setup I use. I have my Aker in my jetpack, being a Jango, I have no pouches. It’s plenty loud and the echo from the jetpack gives it a cool effect.