I have had my share of header gasket sealing issues years ago so now before I install a set I put ink on the header sealing surfaces and very lightly hand file them one at a time in an x-pattern with the widest file I have until the ink is gone. I can get years of use out of the cheapo white Mr Gasket paper gaskets once the header sealing surfaces have been hand filed flat.

If you don't want to pull the headers out to file them then adding a thin coat of copper rtv to any gasket helps seal up any small imperfections.

The most bulletproof gasket setup I'm aware of is copper gaskets along with copper rtv.