After having pulled rear drives and swingarms about a million time during my 42 years of guzzi ownership, I have the following to offer...
If you want your rear axle (talking pre spine or CARC here) to easily come out or go in with only fingertip pressure do the following.
Install swingarm
Attach rear drive unit with the nuts loose
insert wheel and engage splines
Deal with brake, drum backing plate or caliper hanger
Run the axle through
(important stuff here):
tighten the axle nut first
then tighten the rear drive nuts
then tighten the pinch bolt
Why does this work? The rear drive studs in the swingarm have a bit of slop, by inserting the axle and tightening the axle nut, you draw up the entire wheel and rear drive assembly, and the pinch bolt area forces the axle (and rear drive) to be properly aligned. You should never have to hammer an axle. Similar tips for the front end exist, but there it gets trickier due to dampers or tapered tube tops etc.