Managed to fit the two main wheels on the Sea Otter today. I wanted a detachable wheel option, just in case I ever fly it as a water plane in the future. So drilled a hole in the hull directly below the CG mark on the wing, I inserted a drinking straw through the holes and glued it in place, externally and internally (to seal against water leaks). I then placed a carbon fiber shaft through the straw as an axle, placed some spacers between the fuselage/hull and the wheels then used collets to secure the wheels.
I can easily remove the wheel assembly, plug the ends of the straws (not necessary just cosmetic) and she is a sea plane again.
I still need to set up a front nose wheel, that's the next job (it also needs to be detachable). As the project is not finished, I have no photo's yet.
The Rudder appears quite effective for directional corrections on the ground, so the nose wheel doesn't need to be steerable. Once the plane gathers some initial momentum, the front will lift off the ground anyway. So the front wheel will be pretty ineffective anyway for steering.
I will keep you posted and will supply photos later, incase anyone else fancies doing the same modifications to their Sea Otter. That way if you are land locked, you can still build and fly this model