do a search for band adjustment, some do it and say its simple to do, believe it takes a certain allen wrench to tighten them, not sure on this. I myself won't do it, but i buy my transmission filter kit from Geno's actually had one come in last thursday to have it done when i take it in for yearly inspection, I know that my 47RE only take 5qts with filter change, as for the gasket, they are reusable but just to be safe i always get the filter kit which has a new gasket with it.
Good Luck with it.