NONE !
Hi Clayton, I wouldn't add any. Just drive it. If you get a little 'growl' when turning sharp corners in a a parking lot, and you find this annoying, then add a a little of the LSD juice.
The problem is is that the LSD is a stack of spring loaded clutches, if you want them to grab and hold [limit the slip] then you don't want them to have the slipery additive in the lube. If you can't stand the noise from them grabbing and releasing when they have to release around tight corners then give the lube a little additive till the growl just goes away.
Otherwise you might as well have an open differential if you add too much additive.
Hope this helps. Greg L
Ps did you get the 40 installed yet??