Hello,
Yes, the switching frequency in this case would be changed based on the capacitor between FSET and GND using the following equation (page 15 of the HFC0310A datasheet:
I suppose in this regard, you would be taking into account of the FCC band you were speaking about. Be sure to check the datasheet for other components in the datasheet that would need to be sized based on a different switching frequency as well. I am not sure about an exact transistor that you could use, but feel free to size this relative to your own target application.
Hope this helped. Let me know if there is anything else you wanted to follow up on.
Best,
Krishan