I placed sensors on the tubing an equal distance from the corresponding exit fitting using foil tape ....
I took reading this way, and then covered the sensors with hot melt (which i have learned has the same thermal properties as tubing +/- 5%) to protect from outside heat sources and ran the temps again
Both tests Delta temp were identical. The sensors were used on a known temperature to start and were spot on.
The results were taken after 30 minutes idle and 30 minutes into 100% load test
@ 22 Ambient room
Delta T Radiator out / CPU block out 3c
Delta T Idle to 100% load stress test 18c
***if anyone else plays with this stuff I would like to hear your results if you care to post them