i never jack the engine up, just make sure when you have the rocker cover in place, the seal is still in the groove and hasn't been knocked by the cam.
as to putting the sealant on the corners, i put a 'dolop' on the head where the joins of the cam tunnels bolt on, at the front of the cam of course, and i always run a smear around the bottom of the gasket just for added security.
good luck with it anyway