Art - the picture is a little deceiving, the Accusump does not dwarf all other under-hood items!
I have it plumbed into the
oil cooler return line, and yes, there is a non-return valve to make sure the
oil goes where it is needed. Electric solenoid on the end of the Accusump.
I bought a -12 flap-valve type non-return valve. These have the least resistance to flow of all types of non-return valve, although they are not cheap. I don't think a non-return valve is "optional", it needs to be there to make sure the
oil goes where it is needed. No point in sending it backwards through the oil pump and into the sump.
I ran all my oil lines in -12 size, a sensible thing to do IMHO.
If it helps, the flap-valve was cat no CVF7-12 from the Mocal folks.
This pic gets things into perspective. In it, you can see the heat-reflective covering I put around the Accusump to stop it over-pressurising due to hot air from the rad (hmm, nice and shiny!!: