Welcome to the madness.
All good suggestions going here and I'll add my .02 worth. Definitely make sure the radiator is completely shrouded. Any air not going through the radiator is wasted. In general make sure there isn't any air in the cooling system. I use distilled water with a bottle of Water Wetter and about a quart of
antifreeze just to keep the PH honest. X2 on checking the gauge to make sure it's somewhere near accurate. Laser thermometers are pretty inexpensive.
Get as much air out of the engine compartment as possible. Poke arount the ERA website for the vented wheel wells. Every little bit helps. Try a test with some sort of soft wedge (rolled up shop towel) under the rear of the hood and see if that helps keep the heat down. If there is a significant difference look again at some way to get the hot air out. A couple of the folks in our club are running vents or louvered panels in the hood to help with cooling.
You might also try a lower temp fan switch to catch the temp increase sooner. look at different models of fans to find the most efficient.
Keep us posted on what you do. No end of experience out there on correcting the problem.
On a side note keep an eye on the Mile Hi Cobra Club site for their annual Cruise Colorado event. A great run and there are usually a few cars from Texas that come up along with us other foreigners from Oregon, Illinois, Ohio etc.
DonC