You should have more than 22 inches. How tall are the rockers? Those trucks have a 26" tall fender on the rocker. Rocker can't be more than 2" tall.
Some trucks are different from the factory. I've gotten stock fenders that don't fit for shit, or have a different wheel opening, or are slightly taller.
Works out to 23.9". 205/35/18 would be 23.5" tall. Toyo Proxes T1-R comes in that size. Sometimes the tire is smaller than its rated. My 205/40/18s are supposed to measure 24.6" but they measure about 24.4" tall mounted. Also the width of the wheel can reduce the height of the tire. Say you run an 8" wide wheel it would reduce the height. 7.5" is probably the widest I would go with for a 205 tire though...