My two cents...
It all depends the style you're after and the bass you play. Slapping a Zon and then a P-bass... you'll have to hit the pbass much harder.
I was pretty shocked when I saw Louis Johnson on videos... this mofo puts a whole lot of energy to get HIS sound.
If you play late 70s early 80s-style funk, there's not a lot of notes, and you really got to hit em to make it sound right. For modern, more progressive stuff like Ray's or Victor Wooten, you'll need a smoother approach.
I feel more confortable hitting pretty hard myself... just practice what seems RIGHT to you in term of sound and feel
