360 timing cover install- Help!

Tried to install timing cover on my 360 today, in the car. Made a real ultra back sealer mess & gave up. Couldn’t keep oil pan rubber seal in place. Had to trim bottom cork gaskets since I didn’t remove oil pan. Got too much sealer on them & they squished out. Pretty much of a cluster noogie. Looked like an explosion in a gasket sealer factory by the time i took it off and on a dozen times. Haven’t done it in 30 years & it shows.

Going to try again, hopefully better prepared. Anybody got any tips or tricks?