Time for a big tire. Which one?

[WWhunter]

My opinion only, but I personally would not even think of putting the 26" Goodyear 'blimp' tires on a Kitfox. I recently sold a set that were in like new condition. I originally had them on a Champ and then tried them on my RANS S7. The tire has pretty stiff sidewalls for both of these light planes. About the smallest plane that I think they are good on, would be something like a Super Cub. They are heavy and stiff enough that I wonder if you could run them with no air.
I then bought some 26" ABW Airstreaks and they were near perfect. Since you don't want to go with those, my suggestion would be the Desser 8.50 smoothies.
I am now on ABW 29" Airstreaks, and they are more than I need. I am going to get a set of the 8.50 smoothies to use when I travel to paved strips but keep the Airstreaks for 'playing'. Desser also makes a 27" but you would need 8" rims.
The other tires will fit your Grove wheels. Not sure if you can fun the 8.50's tubeless on Grove wheels, but you can on Matco wheels. Probably a way to seal the rim halves on groves wheels also.