A DIY for head gasket replacement can be found in any shop manual

Since you have done a B16A1 swap, get a shop manual for a car that came with that motor stock, this should supplement a manual for your CRX.

As for the 1-layer head gasket, idk. What I would do is call around to some specialty shops in your area and see who knows what you're talking about, then go from there.

BTW, I like the dark look to your CRX. It's kinda the direction I'm going with mine eventually.

Good luck!