The more I think about it, the more I think it might be easier to make the oil return to the oil filter adapter block.  I'm pretty sure that's how it's done on the FD.  Of course then I'd have to find a plug for that oil return hole in the rear housing.

Thanks,
Rusty (let the scheming begin)  

 
 

Rusty, I’m not sure you are talking about the same hole, but I’m using it for redrive oil return.
Buly