What kind of head gaskets should I get? I've only used simple Felpro's, but wondering about a thinner copper gasket?

10:1 BBC, stock head bolts, heads are new surface, block is still of old...

So any opinions or tech info of which would be better to seal?

It's a bit of a pain and I would only do this if I was building a new motor but we use to have the block and gaskets cut for stainless steel O-rings and used a copper gasket with head studs.  We had many instances where the heads had to come off at the track for spring replacements and the ability to reuse the copper and the ease of prep made the change much easier. The one challenge was getting the gasket off the head studs in order to clean the deck and anneal the gasket each time the head came off. Now days I hear that springs don't break as often as they used to (maybe the cam lift isn't as hefty as what we use to run) so the need for so much at-the-track maintainance isn't as necessary as it once was. We were running about 12:1 in what was basically a late 70's match race Pro-Stock motor for Comp-jet.