When we first contemplated buying our 25, we planned on putting our 21' double kayak on the roof. We were going to use the C-Dory to get to remote kayaking locations. After getting the boat and thinking it through, we realized that it wouldn't work well. The kayak was 100#, 21' long and cumbersome.
We now have an 8' inflatable and a 2 hp Honda. The inflatable weighs around 42 lbs. Believe me, getting even 42 lbs on or off of the roof in anything more than a breeze can be a challenge. I love the look of the hard shelled dingys, and they row better than an inflatable. However, I don't think they would work well on the roof of a 22 or 25.
Lyle