just buy one tire 5.50x16 and try it.
if it fits properly then buy the other one, you will have no problem selling the 6.00x16's
your tires must clear the frame bolts.
only ever seen one of these tractor and the old guy no longer has it, so i can not go down and check out his front tires for you.
note to file: he had a set of front cultivators for it, what a great tractor to plow corn with.