Gary
I have no idea what sizes these sort of tyres are manufactured in but personally I would have thought the selection of sizes would be somewhat restricted in comparison to normal full sized road tyres. I suppose the way would be to do a visual comparison to make certain you have a pair of wheels with the same diameter/height and rolling circumference. Other than that I would still be very sceptical about safety and any damage that might be done. E.G. to the differential unit.
Best Wishes and Regards, John