I think the 24 is lighter than the TC 255. I have a Ford 250 Super Duty 4 door which tows the TomCat OK, but it will groan if you try to maintain speed on steep hills.
Most TC 255 owners think a 1 ton is the best. My 250 Super Duty is rated for 13,500 pounds and I think the loaded boat, engines and trailer run about 11,000 pounds, so the actual rating of a truck may still mean slowing on hills, etc.. Having said that, if you are not in a hurry, nor frequently doing thousand mile trips, a 3/4 ton does well. I take mine from Wichita, KS, to Houston, TX with no problems and that's about 700 miles.
I got the 250 (3/4) ton because MOST OF THE TIME, I do not need a 1 ton, so could not see wasting all the extra fuel for the many more miles it was used without a boat behind it. I have now purchased a small economy car for most running around and a 1 ton might make more sense now, since I would use it only for towing.
So, it depends on your situation. If you have an economical car or small pickup for general use, now is a good time to get a good deal on a 1 ton which would mainly be used for towing. Those 1 tons of all major makes hold up well, so a bargain on a used model would probably work well.
The TC 24 is shorter, smaller and lighter, so I'd guess a 3/4 ton ought to work OK there also. If you're thinking of a small camper on the pickup, a one ton would be better to handle the extended hitch.
John