Hi Nick,
the 550's are good, it is just the 24's are so much better, bigger wheels make them much easier to push/manouver around. Lifting the motor doesn't help that much because it still leaves the skirt dragging on the grass, increasing the diameter of the rear wheels will lift it, I'm still trying to work out how that could be done. Bigger front wheels fairly simple. Only other way is to cut and weld the arms the axle is on and lift it that way but that is quite difficult. Anything can be done it depends on how much time you are prepared to put into it. This question of what to use in this situation you have is not new it is a problem we have discussed here before, if there was a machine that would do it we would be all over it.
