I've had 100% no leaks on my last 4 motors with Remflex gaskets. I've tried quite a few over the years, Percy, Hooker, Mr. Gasket, Cometic, JBA, Hedman, Dynatech, Annealed 5052 alum, Dead soft copper, and others. tried matching surfaces to the heads and doing away with the gaskets (one of my not so bright ideas...) Sorry, truthfully I typically throw away what ever gaskets usually come with a set of headers and use the Remflex.
I stick with ARP drilled header bolts as well and use .025" inconel safety wire. Mucho better than Percy locking header bolts (unless you enjoy installing heli-coils) or fumbling with Stage-8 c-clips.
FE Engines - 332, 352, 361, 390, 410, 427, 428
https://www.summitracing.com/parts/arp-400-1205