Well first let me congratulate you on the double . I also shoot a double with fixed chokes . Standard full/Modified . I have patterned several brands and loads since getting this gun . It prefers WINCHESTER XX SUPREME MAGNUM #6's,,2 3/4 inch ,,,,1 5/8 oz.
Longest shot to date is 39 steps for a longlegged feller . I also was anxious to try out the Fed.TITEWAD loads when they first hit the shelf. All I could get was #4 shot . My gun performed terribly with these loads . I don't know or have any idea why . Every shot was at 25 yards into heavy cardboard , and each wad went through the card ,,,,,,kicked like a young mule too.
I hope you enjoy hunting with it as much as I like mine . I like the two choke choice for upclose and out to 40 . I prefer the bird inside 30 . Most of the birds I've taken with this gun fell to the modified barrel.