What do you use for header gaskets?

my experience with the coppers wasnt very good. They worked fine at first but then they need tightened every week to keep from leaking and "spitting".. The best thing I have found and is working for me right now is to double up the Mr Gasket gaskets as you have done but make sure you have lock washers on the header bolts. I use a mix of allen head and 6 points (don't particularly care for the 12 points ) with just a wee spot of aviation form a gasket on the threads (careful don't drown them). I run then till warm and snug them down then when cold I snug again and then never have to touch then again.
PS. I am running Hedmans too