I'm going to have to revise point number 2 above after further experimentation. That orientation seemed to be more tolerant of the occasional air gasp resulting in a more complete drain of the bags but it ended up priming less consistently. Not sure about the physics behind this but I guess I'll have to go back to the drawing board about how to address my draining issues on my rear bags.
They worked great when the pumps were screwed right into the bags accept for the issue of the pumps being pulled out of the threads but ever since I went to this setup between the bags and T800 pumps I've been fighting priming and airlock issues:
FWIW "3/4" FlowRite, and Barbed Fittings are significantly smaller in ID than 3/4" NPS on the T800 intakes and what not. I assume that 3/4" NPS is based on the OD of a male fitting and all of the fittings are the size of the OD. The Flow Rite and barbed fittings are based on the ID of the 3/4" hose hence they are smaller. My point being that if you're going to use 3/4" hose and fittings like in the above picture on the intake side of the pump it imposes a significant restriction relative to the ID of the pump intake.
I may redo the whole drain operation for the rear pumps. I'm thinking about turning the bags around. I've currently got the drain pumps on the front of the bags because there's space under the seats to clear the pumps and this was the way WakeMakers recommended. I'm thinking about putting 1" fittings with a 90 and 16" or so of 1" hose so that I can mount the drain pumps low on the transom. I'll just cram the 1" hose over the 3/4" NPS intake of the pump and secure it with a hose clamp. I'll put the pumps low enough that the water will naturally drain to the pump.