Trans pan gasket..sealer or no sealer?? and other trans ???

As Snake said, if the surfaces are true there's no need for sealer. As for the adjustment, that's the rear band adjustment. Most are single wrap rear bands that are torqued to 72 inch lbs. then backed off 2 turns. If it's a double wrap band they are adjusted to 72 inch lbs. then backed off 4 turns. Don't forget to adjust the front band too (the adjustment is on the outside of the case above the shift linkage). It's adjustment is really more critical than the rear band because the rear band is only used in manual low and reverse while the front band is for 2nd gear application. Never had a trans. squeal. Are you sure it's the trans? Are the belts tight? That's the only thing I've ever had squeal. No reason at all to not use Dexron. Whoever told you to stay away from it don't know squat. Using type F is an old trick that made them shift a little firmer.

BTW: if the fluid is burned the trans. probably won't last long. Was there much "mud" (friction material) or metal in the pan?