I'm in the middle of this myself.
While you are waiting for the gaskets to arrive, take a good nut and spin it on all the cylinder head studs. If it binds on any of them I would replace them all as it may be a sign that they have stretched.
The head and block may be level but could you slide in a 3 thou feeler gauge anywhere under the straight edge? My local machine shop surfaced the head for only $35. It is now of course perfectly flat and clean and I can now rule that out as a source of the problem.
After installing the new gasket and if the dipstick shows just oil down there and at about the normal level, I would run the engine til it reaches operating temp, change the oil and filter and do the second re-torquing of the cylinder head nuts.
Moss Motors gasket is a Payen, which by all accounts is good enough, but I just got another one, from a Moss distributor, and it is a County brand, but made in England so I think that should be OK.
Cheers and good luck!