I still think that the only meaningful data would be obtained by using a non-restrictive flowmeter in a closed system. I will attempt to get this, however I think that all the numbers that can be obtained will mean less than the answer to a simple question: "Does it work?" yes or no. 

I agree.  I think the ideal test would be a flow meter installed in the same engine/rad/hose combo, first with the mechanical pump, then with the electric.  It wouldn't really be all that hard to do during the ground run phase, but I'm certainly not asking you to do it.  If you seem to be getting good results  with your electric pump, I might consider doing the test when I get to that point.  

Good luck,

Turbo 13B powered RV-3... Be Afraid :-)

1993 RX-7 R1...  Both turbos working!   (at least temporarily)