The smallest amount possible and only between the splines, not on top or down at the bottom of them. What you want is a light coating between the splines where they contact each other. I normally use a Q-tip to dab the stuff between the splines on the final drive and as long as there is any at all, I call it good. You absolutely do not want to pack the splines full because it is a total waste of paste plus all the excess will be flung onto your rear wheel anyway.... where you will have to clean it up.
A small tube of the Honda moly paste, which I think is about 3 oz., should last a lifetime (a human lifetime- several motorcycle lifetimes).
Brian
Curious how much of this moly paste to actually apply on rear diff before I reinstall wheel. Cleaned everything since I had the wheel off to have a new tire put on. Do I just brush a thin layer on the gear that inserts into the wheel or should I pack some into the wheel also, thanks