Ballistic Products publish a handy loading manual for 10 gauge, (and other manuals cover such things as slugs, buckshot, smaller gauges, bismuth, etc). The 10 gauge one covers the range of possibilities. I don't have the latest revision but those I do have include light to heavy lead loads, steel, bismuth, short loads, different cases, powders, primers, buffer, you name it. Perhaps not black powder. They also sell what you need such as 10 gauge wads.
Some items added to a shot column add little or no pressure to the load and so some fillers like cork or cardboard can be added to take up the space of the subtracted shot. In that way you still get a good crimp on a light load. If you're using a Mec loader, you can purchase a shim to load short loads without having to adjust the loader itself.
2 ounces of lead-BB's is a good Canada goose load. Loads like 1,1/2oz is a good off season one for rabbits and similar to help you get used to swinging the heavy barrel/s. I've only used factory steel loads but I have loaded bismuth in 12 gauge which included making by own bismuth shot.