Either nitrate or butyrate will be satisfactory to seal the fabric with. Its better to brush the seal coats in order to work the dope into the fibers. If the first coat is sprayed it will tend to lay on the surface and not penetrate the fibers well. If butyrate is used for the seal coats don't use nitrate over it as it is not compatible. If the first coats are nitrate, butyrate will go over it OK. You can use most finishes over butyrate. If you use latex for the finish coats you are just adding weight compared to using aircraft dope. If you have facilities for spraying dope, it doesn't make much sense to use a latex for finish.

I'm curious as to why you would use a fabric of unknown properties when for just a few dollars more, you could use Sig Koverall and know exactly how it will perform.

I would also recommend using a full scale fabric cement such as "Fab Tac" rather than Stix-it. I've used Stix-it and it works, but the edges tend to fray and it's hard to trim the fabric. The fabric cement has the right amount of tac making good seams easy and it holds the strands together so that it trims without fraying.