It looks like you might have room for two small puller fabs mounted diagonally in the upper left hand corner and bottom right corner. If you leave the pusher then the 3 fans should cut it.
Thats certainly an option, much appreciated. I'm looking at a number of possibilities. My first move today is to drain the radiator, pull the thermostat, and will boil it on the stove to confirm when it's actually actuating - making sure it's not defective. Then I may try running without the thermostat to see if the most simple solution works first. Additional puller fans are another option I would consider, all the way down to full on custom work to relocate the radiator - but would rather not do that if i don't have to.