I have set up alot of fishing cats , hundreds. I actually prefer to fish from a cat in technical water. They can get sluggish if you overload them. You are going to want at least a 14. I run 14x24 tubes for extra floatation. Here is a cat frame that runs a passenger in front and one in the rear and it balances out the boat great for fishing. You will hear lots of get a raft but it really comes down to knowing how to set them up and knowing what kind of performance to expect from how you load the boat. The frame shown is only 82lbs for as big as it is with 2 dry boxes ,1 fish box, removable backrest,swivel lean bar, hard floors etc,etc.
Most of the modular frames are excessively heavy by the time you load them up with fittings. Ther are alot of mistakes people make when putting together fishing cats that kind of gives them a bad rap. If you know whats up they work pretty well.