This I will check out.
The plans call for a 4" wheel but I might shrink it down to 3.5 or 3.
From memory there is a fair bit of the spar to be removed as the 109 wheels retract outwards & at an angle to the rear.

I also have to try and find some skinny wheels that will sit inside the wing.

I'm sure someone has tackled this problem before, just gotta wait till they show up here