You may want to look at RemFlex gaskets. They are thicker and more forgiving of any mismatch in the flange and head.
I use them on the header to the head, and also the header to side pipe. It took me a while to figure out how to get them to work on the side pipe. If I remember correctly they only require 10 LB/FT of torque. What happened was the bolts would come loose and then I had a leak. Finally I went with flanged nuts and star washers. No problems since I did that.
Here is link to their site.
Remflex Exhaust Header / Manifold Gaskets