I have a pair of copper gasket that look just like your, leaking everwhere they could. I hung them on the wall and bought the laminated aluminum gaskets. 15,000 miles later, no leaks.
I think the headers that most of us use are not straight and most header gaskets will not seal. The aluminum laminated gasket works best. You may have to use more than one. Mike and I peeled them apart and used one and half per side because of the warp in our flanges.
I like the Stage 8 header bolts, Mike hates them.
Dwight