The favored brand of transmission fluid is Coastal from Autozone. It tends to be a little thicker than the Advance brands. (Right Don
) Get yourself 2 of the gallon containers if available. I find a pan drop takes 6-7 qts.
The gasket GM orignally puts on the transmission is considered a lifetime gasket. It can be wiped and reused until there appears to be a problem with it. You can easily tell the GM gasket by the metal under rubber with ridges. (I can get a pic later). Aftermarket gaskets that come in trans service kits are usually just a big stamped rubber gasket. Do not use any gasket sealer.
A good Craftsman clicker torque wrench is all you should need. I would be wary of say a Harbor Freight one. Although I am sure they do work.