I've done two guns with duracoat shake n spray kits. Very happy with the results on glock frames. My edc G23 shows ZERO wear after a year+.
Just follow the directions on prep and degreasing, and give it time to cure.
I used the ultra-flat tactical on my first gun, but a "regular" color on my next project. Must say I prefer the ultra-flat. Not nearly as slick and shiny.
Forget doing 2-3 guns, as advertised. No way. Buy one kit per gun.
First pic: G23 with ultra-flat coyote
2nd pic: G30SF with Air Force green (not ultra-flat)
I tried Alumahyde II several times on random objects (knife handles, etc). It certainly does the job, but I like duracoat much better.