Gary,
I know a lot of knowledgable guys go for tandem axles, but I can give you my experience. When I bought the Hunky Dory the factory, Mark Toland, said "stick with single axles", His reasoning was the frame and construction of a single was heavier than a tandem . At least the EZ loader was. I have pulled the Hunky Dory well over 60,000 miles. Three trips well down into Mexico. Several trips to Florida, which is 3000 miles from here in Montana. I am on my second set of tires is all. I carry two spares mounted on the trailer. One is on a free turning spindle on the front hitch bar. It can be used to run trailer across the sand by hand than winch it back up off the beach. I have found it is plenty adequate for a 22 ft. C-Dory. Much cheaper to replace two than four. Just another side of the coin to think about.
Capt D