I have never heard of the caps getting hot and breaking off, but just a thought, if you like the wheels you have, how about using one of the later, shorter style, that snap on the lug nuts?
My thought is that being shorter they might not be as much bother, and would also make the wheel look deeper?

I went with the '03 or so 17", I liked the design and thought they would look good on a square Dodge, but overthought the wheel adapter/hub centric, spacer thing ... these are 275/60-17 tires, 2" rear spacer and 1" front, rear would be better with 1" also, or 1 1/2".