I sort of struck out on the gaskets. I found plain o-rings at the hardware store that would fit the machined area on the 'bolt' (I don't know what you really call it) from the one piece unit, although I am not certain it really requires one as the two piece one does not have the machined area in its bolt. I also found an o-ring that would probably do ok for the bolt that attaches the right angle adapter on the two-piece unit, assuming that a standard plumbing o-ring is safe to use here. Ace also had a large o-ring that might work for the point where the base attaches to the block, but I would be concerned about using a standard one there.
So, on to AutoZone, where I tried out basically every filter that looked like it might work, starting with a PF-16, which was the stock filter on the Turbo Coupe and the Alpine. That gasket is pretty perfect for the point where the angle adapter attaches to the base, but just a little too small for the block attachment. Unfortunately, the block attachment is the critical one for either cooler. I Googled the topic and found lots of people who said they were able to make the PF-16 gasket work, but I don't see how. I also found one of two potential sources for them and am waiting to hear back to see if any pan out. Baring that, I am thinking about flipping the original ones over and setting them in with a small bead of silicone gasket maker. I am thinking that bead would be just enough to raise the profile a bit and ought to allow the original gasket to last a lot longer. Does that make sense, or am I about to do something bad?