Woody....
Your references around 3:30 in the video

Factory - 1.5Gal/min
LET Cooler 3.7Gal/min
Waldig Supercooler 3.9Gal/min

Are these off the JohnsonCM30? Just checking

Just to normalise....I'm sure I read somewhere that the stock IC+ Bosch pump will do 10L/min 2.6Gal/min.....
I'm hopefully installing my RTD's in line with the SC this week, but the Hall effect flow meter may take a little longer as its a PICAxe job. So I want to assume a flow to start and I was going to use 2.7Gpm
I'm suspecting the flow wont change between hot and cold running. But I have other plans for the PIC.