Okay, so let's break this down. First, viscosity: the difference between 5w20 and 5w30 is about 8 degrees Celsius, and the same again between 5w30 and 5w40. Second, the higher the viscosity, the harder it is to pump, which takes energy that's absorbed by the oil and that means that thick oil runs hotter than thin oil under the same conditions. This was glaringly obvious in my E39 M5 that was approved by BMW for both 5w30 and 10w60. Track day running temps were noticeably lower for the 5w30.
So that's why I'm not convinced that all the concern about viscosity is as important as it seems - the higher the viscosity, the hotter the oil, the less "extra" viscosity. And then there's Dr. Ali Haas, who was on BITOG for years. He argued that the thinnest oil that maintained adequate pressure was the right oil. His view was that thinner oil flowing faster would carry heat away from the hottest parts of the engine faster so that they'd be cooler than they'd be with a thicker oil flowing more slowly. The argument has merit. He ran 5w20 in his Enzo, which was rated by Ferrari for 10w60. Had he tracked it, he might have stepped up, but he'd have done it on the basis of oil pressure at high RPM, not what the manual said.
So, if I had a 2016 GT PP1 that's still under warranty, I'd run the oil that Ford recommends, add the oil coolers that Ford recommends, and I'd change it after every event, again as Ford recommends. Once it's out of warranty, I'd switch to a 5w30 that's on the Porsche C30 list. It'll have an HTHS of 3.5 or higher and it's low SAPS. If you don't care about SAPS, you can also switch to Redline 5w20, which has an HTHS of 3.2, more like a US 5w30.