Great! Good news and bad news.
Good news is that it seems the simple "set the radiator in the hvac return" works. I proved so by forcing all (not sealed but you get the picture) through the radiator:
With the above picture, there were zero changes in the temp.Now for the bad news.
This may not be helpful for others. I used hard fittings to connect to my CPU, and it is a huge pain to pull out. Worse yet, it's possible the fittings are pulling the CPU block off the surface of the CPU or otherwise lessening the pressure of the springs on the EK CPU block.