Richard,
At risk of being tarred and feathered, a suggestion. If you have the older Hodgdon reloading magazine they list a number of loads if 11-1200 fps works for you. Look at 7/8 and 1 oz. loads using 7625 and PB that stay in the l/t 6000. You are set up for roll crimping, cut back the hull of your choice from the load selection to about 2.35"--just below the star crimp. I prefer Federal Gold Medal hulls as they roll crimp to perfection. Using any of the major brand wads--Win, Fed, CB etc--the loads will fit nicely. The reason I'm about to be lambasted is I've read that shortening the hull can have adverse effects on pressure. IF my flawed logic applies, it doesn't make sense. I'm not forcing components, I'm only changing the crimp and I've also read that roll crimping will show a tad less pressure than star crimp. If you can't get your hands on the Hodgdon catalog go to their website for exactly the same information.
Good luck, and I sincerely hope your post gets some additional response. I'm sitting on a couple hundred Gamebore hulls I'd like to load. Despite what I said above, I'm too much of a wuss to wildcat with a shotgun.
Steve