This answer is probably headed in a direction different from what you are asking. Whatever minimum curve you are running has no bearing on the switch size. You easily can run 072 switches with your 060 curves with no issues.
Back to what I surmise is the core of your question. If you have engines/rolling stock with a stated 054 minimum, you would be well served to not use switches tighter than 054 (say 042 for example). Minimum radii have more to do with switches than curves.
