I know a lot of people have trouble with header bolts coming loose and having to use all kinds of fancy locking bolts, but I have regular Mr. Gasket bolts from CTC and have never had a problem. I installed them, let the car warm up for a bit, tightened them again, then took it for a good drive and tightened them one more time. They've been on the car for 5 years or more with no leaks and I haven't touched them since being installed.
I used Mr. Gasket Ultraseal gaskets (#5900 IIRC) FWIW. Gearwrenches are your friend