Will there be enough room upfront to install a 72R engine cooler and a 19R tranny cooler?

no because you will block off the radiator flow. that 72 is really wide plus you have the power steering cooler as well.

The Vegas heat is much worse than you think. Highs during the summer are 110-115. The asphalt is closer to 180. Sitting in traffic will cause a lot of heat soak alone. No it won't go into limp mode in traffic, but I might be able to just romp on it once or twice and it will be outside of recommended operating temps. Yes a 25 or 34 row will be okay, but maybe I'm a bit overzealous. A $70 difference to get this kit is definitely a good deal. There is still enough surface area on the radiator to maintain good temps on your water, don't let them sway your decision if it's what you want.

As I said before the surface area of the 34 and the 72 row Setrab cores is the same. The only significant difference is that the 72 row has shorter fins and so causes less pressure drop, and can flow at a higher rate.