There's a guy on Ebay named Gary selling gasket sets for the Tillotson carbs. Send him a private message through Ebay and see if he can make one up for you or what he has. I emailed him about my Tillotson SP13B and he said he'd make a gasket kit up this weekend and he's working on the needle valves etc and should have them soon. Not sure what he can do for the R6A, but its worth giving him a try.
Where Are You From? Oviedo, Florida
Do You own a car built by Durant? 1928 Durant Model 65