You should be fine- H2on22's tows a Kachina 26 with 22's.
I tow with some 20's, but the tires are 35 series, very small, and I have never had a problem towing around 4000 pounds.
I know a couple of others that have Denali's with 22s, 23s and one guy with an H2 and 24s, all tow big boats and never had a had a problem. Post some pics of the wheels on the vehicle-gotta love 22's.
Good luck-
Roln 20s