Yeah the stock handgrips seemed very tiny, like I was gripping a #2 pencil. So I added grips right away. I've put them on all my bikes and yes they work fine with the heated grips.
I mentioned the small diameter to a Goldwing rider friend, he commented "I guess it's what you are used to". Then he laughed. Took me a moment to get the joke.
Soapy water and air from compressor eased the install. It's like riding a new bike.
I had issues with my right hand going numb on my ST1300, had hoped it was riding position or vibration specific to the ST, same thing on the F6B.
After just a day with the puppies it seems the numbness may be gone for good.
I don't have massive hands but the stock grips are just so small. The larger diameter also seems to allow finer control.
Fantastic upgrade!!