. . . the new cooler goes on next weekend. . . .
For the sake of the tranny, run the new cooler in series but after the existing cooler in the radiator. The reason is the engine comes up to temp sooner than the trans and the trans will last longer if its brought up to temp sooner. In the race world "who cares", but a daily driver = yes!
Also, take the time to mount the new cooler with something other than the pull ties which hang it on your condenser (assuming you have A/C yes). Time and vibrations can damage the condenser so use some metal strapping and nylock stainless bolts/nuts.
Here's a good place for another tip:
Barbed fittings with hose clamps work well for keeping rubber hoses on. The problem is when we make custom metal pipes to connect accessories we end up with tubing with no quick way to connect rubber hoses. Here is a solution:
Take a 5/16 or 3/8" steel brake line tubing and form it to fit the application.
With a brass union coupler and some RED Loctite, apply Loctite to the end of the tubing.
Slide the nut, the ferrel, and the union onto the tubing.
Tighten the union tight enough to collapse the ferrel onto the tube displacing the Loctite. Remove the union and the nut. You tubing now has a rounded hose-barb that keeps the hose from blowing off. This is much better than doing NOTHING and hoping the hose never blows off the tubing.
This is nylon tubing but the principal is the same. Steel does not use the insert in the core of the tube so disregard that. Slide your rubber hose over the brass and secure it with a hose clamp. Done!