I am the second of apparently currently four people to do this (saw a picture I believe was from PhilJ awhile back and replicated, but this pic is my bike)
Timing straight to Primary (there is never pressure in the primary itself, just timing, so it's still okay to use ATF), and crankcase up and down onto the chain (up so most will drain back down). I think the others route it back to their rear wheel, but whatever works.