As far as the orings, I have read that if you grease em the grease can get into the groove and make it harder to seat. I just squirt a bit of motor oil on the orings, coat the d/s splines with good marine grease and it usually goes right on after setting the gimble bearing with the tool, about 1/2 the time, I have to give the driveshaft a little turn.
Kind of like doing a clutch on an old air cooled VW, the engine would not slide all the way up to the trans axle unless you put a spark plug socket on the generator pulley nut and turned it just enough for the splines to line up.