Hi Nick,
As you have found out Victa are the only mower that uses a 9/16th axle the others use 1/2 inch, always makes things hard. A self propelled 24 would be the ultimate machine but nobody ever though about building one. One other thing with them they have a much better balance point than the 550's so the are very easy to operate with the front wheels up in the air, they balance easily on the rear wheels and because the wheels are bigger are easy to push. I know how heavy those Hondas are that aren't self propelled and the 216 when the transmission fails are near impossible to push around
