Let me tackle the launching issue--I have single handled launched both boats, mostly behind a diesel truck--but also the 25 behind a 30 foot RV, and down some long ramps--which attracted a crowd!
The C Dory 25 sits a few inches lower on the trailer and can be easier launch at very low slope ramps (example Lake Powell)--but in steep ramps (most in the PNW and Calif), this is not a problem The Tom Cat, because of the hulls width has to sit on top of the fenders--and I have 16" tires (a bit oversized perhaps--and you can get it a few inches lower with tripple axel trailer. I found that the C Dory 25 was actually harder to center--because it sat between the fenders and there was only about an inch and a half clearance on each side. I didn't have side guides, but did have the aluminum pipes with PVC guide ons, which will give.
The Tom Cat trailers have bunks in the center, which helps to center the hull (see photo in thataway album, so It self centers. We launch and retrieve our Caracal, which has slightly less beam, and is lower, and has both side bunks and center bunks on a dirt ramp with ease, so it is not the hull form.
As for handling--I think that the cat hull is easier. The reason is that both hulls act as keels and the wind has far less effect. Also you have counter rotating outboards set widely apart, which give great turning torque. So the Tom Cat is very easy to maneuver. The C Dory 25 has no real keel, and tends to pivot in the outboard, thus is more affected by the windage. In the water the windage is not a lot different between the two boats. I have never hesitated to take either boat into "tight" spaces. But the nod goes to the Tom Cat.
Draft--perhaps you can take the 25 in slightly less depth of water. I routinely take the Tom Cat out in 16" to 18" of water over a sand bar in our winter low tides--I suspect that you might get the 25 or venture in 14" (but you still need enough water to let the prop be effective and have good cooling water intake).
Rough weather--Some others may answer this better than I--but 3' chop is considerable. As far as big rollers, both boats handle this very well. I have had the Tom Cat in 2 1/2" chop and 4 foot rollers with no problems. If you get to real 4 foot steep seas, both boats will survive well, but be uncomfortable. The Tom Cat may have some "slam" under the wing. But the C Dory 25 will bury the bow. (I am thinking specifically of coming out of Cattle Pass in the San Juans, with a good breeze blowing waves into the pass and and ebb tide which will steepen up and confuse the seas.) Running in a a breaking bar, I would prefer to be in the Tom Cat, because the boat responds so rapidly and has good bouyancy forward.
Some cats will handle going into chop better than the Tom Cat--and these are the semi displacement boats. (Glacier Bay and World Cat) But their top speed is limited, there is more sneeze, and there are some major problems down wind/seas which the Tom Cat does not have.
One other advantage of the Tom Cat not mentioned is the wonderful aft bracket. This acts as a great swim step for kids or divers. There is a good "T" ladder, which can be easily used by divers with grab rails. The dinghy fits between the outboards for boarding--I think the Tom Cat is a much more kid friendly boat. Also the cockpit does not have the splash well, or any of the weakness associated with that. The cockpit is bigger in the Tom cat, because it does not have the intrusion of the splash well.
Note the bunks in the center of the trailer, that rest on the inside of the hulls. The slicks on the front of the trailer make launching and retrieving much easier.
Ignore the blue crate (that is what I put the generator fuel tank on)--look at the area for the entrance into the water from the platform on the Tom Cat.
