Frank,
The Sig, Brodak, Randolph Butyrate dopes are all compatible, you can even mix them wet. Same with the thinners, although Brodak and Randolph are quicker to gas off then Sig, but all work with all the Butyrate dopes. Check Brodaks discounted area for small sizes you might need. Also if you call in the order you can have them ship it by ground at a lower rate just a few days extra in transit.
Best, DennsT