The return fluid from the cooler enters the case, lubes the rear support and then travels forward through the output shaft to lube the planetaries and the input/output shaft interface.

For your purpose, I would think a tee fitting that routes a single line with a control orifice to the rear bushing would suffice...multiple lines might rob needed lube for the planetaries. In your case you might even consider installing a caged needle roller bearing which would need less lube but I don't know if the slip yoke surface is hard enough to survive.

The factory lube source for the rear bushing is a "spine" cast into the top of the tailhousing (red arrow) that depends on a sort of capillary action to route fluid to the top of the bushing where it spreads via criss-cross channels in the bushing. Fluid drains through the rectangular slot at the left.