"checker auto" sells a great "Plate" style cooler "complete kit" I think it was about $30 works very good. about an hour to install.
I would run to the radiator first then the cooler then the tranny. THAT is what the instructions tell you to do.
If you run to the cooler first and then the radiator it would completly defeat the purpose of the cooler
since you cooled the fluid down, and then warmed it back up in the rad, you might as well have never ran it through the cooler in the first place.
I dont think a stable temp is all that important since it is never consistant anyway. It starts out whatever the outside temp is and warms up from there anyway, an I SERIOSLY doubt you can over cool tranny fluid
I would run to the radiator first then the cooler then the tranny. THAT is what the instructions tell you to do.
If you run to the cooler first and then the radiator it would completly defeat the purpose of the cooler

I dont think a stable temp is all that important since it is never consistant anyway. It starts out whatever the outside temp is and warms up from there anyway, an I SERIOSLY doubt you can over cool tranny fluid