Go with a #5...
I vote you go with the #5 turnouts. I did a mock-up test, worst case scenario (turn ends crossover) with my U36C and it derailed 1 out of 3 times without cars on the #4-#4. The U36C, even with a 6 car linked inter-modal trailer carrier coupled to it, had no problem going through a #5-#5 crossover. Here is a visual size comparison:
Foreground - Atlas Code 100 #4's (theoretically a 15" radius curve)
Middle - Shinohara Code 83 #5's (theoretically a 26" radius curve)
Backround - besides the clutter, the U36C 6 wheels/truck test subject
PS: I went with #5's as a ladder in my small 3 rail yard when I rebuilt my layout instead of the #4's - mostly to avoid structure problems with the framework and the Tortoise switches as part of the DCC conversion but it has made for smoother operations with larger engines and longer cars.