Remote Trans Cooler needed or not?

Very grey topic. The tube in your rad is to warm your transmission fluid..especially in winter or cool weather. Optimal temperature is 170 - 190 degrees.Delta T says the bottom of your rad is about about 30 cooler than the top so the fluid is being warmed to about 160 degrees by your rad.The additional 20 or 30 degrees will come from friction.If you are racing or using your vehicle to tow in hot weather i would add a cooler in series with your rad tube.
Monitor your transmission fluid temperature and then decide.
I ran a 4" x 11" cooler in series with the rad on a warm 340 with a Dynamic 9 1/2" converter and it was hard to get the fluid temp to 160 degrees which wasn't good.