I use bolts with a 12 point 3/8" drive. The smaller head help with accessibility when a tube encroaches the space projected above the bolt head. I've found that headers with a thick flange (5/16 or thicker) don't seem to be all that dependent on the gasket.
I've had good results with Spectre 1/8" gaskets. You'll have to look up the PN for your application as mine is for 351c.
