My neighbor has his TC 24 on slings. I have had several boats in the 22 to 25 foot range on slings. The aft sling has to be right at the aft of the boat, so that the weight of the motors on the transom is taken by the aft sling.
Slings on lifts are pulled from the sides of the lifts, either with a single or double motor setup, so there is no issue of "pinching" the boat--in the lifts I have used.
However, I have my TC 255 on bunks (see the Thataway album). I feel that with the weight of the TC 255, it is easier on the boat to have it on a bunk cradle rather than slings. In either case, you have to have a dual motor setup--a single motor is not strong enough both in lift or static mode to handle the weight of the TC 255. It will cost a bit more for the bunks--and you have to have slightly deeper water--but the boat will do better.
What is your situation where the slings might be preferable?