Moving to VA in a few days getting my build ready for my new non-ban state when I get there.

I have a Noveske 14.5" Afghan Barrel that I plan on sending in to get my KAC QD Flash Hider permanently attached via 1000 degree silver solder. Here is my question – “Do I use a crush washer or a peel washer?” Thinking of maybe applying to get a KAC 5.56mm QDSS NT-4 Silencer eventually. Will that make any difference?

Thanks,