Hi Jordan I've been watching your YouTube series. Very interested in the build-up.
You might want to consider running the hydraulic cooling loop through a cooler then to the PTU and then back through a second cooler. Hydraulic fluid can fry from too much heat. It also does not have the same thermal transfer dynamics as ethyl glycol in water.
You might also want to give this a look.
https://www.hydraulicspneumatics.co...885012/engineering-essentials-heat-exchangers
Not that it would be a problem at the track, but transmission fluid doesn't flow until the transmission is warmed up. There is a thermostat controlling transmission fluid flow to the cooler to prevent over cooling under normal conditions.
Cheers Bluezone