Brooksy, I know where you're coming from. I normally get a gun( maybe a ten, who knows?) and then I've got to buy or make some ammo for it and try it out, just because I can and to see what it's like. I can understand doing this in reverse, aquiring oddball ammo or reloading components and using them as intended. It's a shotgun, it's designed to shoot small moving targets, and if your range will allow casual practice with a non official guage go for it, it's a hoot! I would suggest however that a ten as a heavier, usually tighter choked gun , is more suited to trap than skeet.
There is some 2 7/8" data in " Reloading For Shotgunners" fifth edition that will be helpful, these go down to 1 1/4 oz of shot, about the lightest practical payload. As previously mentioned, about the only source of hulls now is to cut down 3 1/2" empties and those are scarce on this side of the US border. Sometimes you can find part boxes of old paper hulled Canuck or Maxum at a reasonable price at a gun show, shoot them on the range and then reload, if in good shape they can be used a few times. Just wath for swollen or bulged cartridges from poor storage, they won't chamber. If you can source the empties try to find some Remington SP10 wads and you should be able to find data. A load that I have used successfully for years in my vintage 1881 Westley Richards in old Canuck or cut down modern 3 1/2" hulls is 33 gr of 4756 with W209 primer, Rem SP10 wad, 1 1/4 oz shot, roll crimp. Not recommending this to anyone else but it works great for me. Have fun. Jim