I have a 4" wheel on my 1x42 and do small HCs once in awhile with that. I watched a video by James McClendon on Youtube and his 4x36 about doing the KITH by modifying his 4x36 to do a HC, so I am going to attempt the same with my 2x48.
I've already made some mods on it and I will use 2 radii, one 3" radius ( 6" round) and one 4" radius or 8" wheel equivalent. Remember radius is half the diameter of a circle. A 6 and 8 would be the sizes I would have. I don't really see a need for bigger. I mean there isn't much difference between the 8" and 10" on a knife. I've seen both and unless the grind is wide it's hard to tell the difference. Dayton is a good base for modifications if you have some metal fab experience and you don't really need a lot either. A 2" wide belt and a 2 1/2" wide platen leaves room for bolt holes.lol
James' video link
https://www.youtube.com/watch?v=eRqhays5vEc&t=33s