Never weighed mine - maybe someone with chime in with a specific, but I always assumed a loaded boat weight of 6000 and a trailer weight of 1000, so tongue would be between 700 and 1050 at 10 or 15%
I don't think it would be quite that high. A C26 would require a dual-axle trailer which would support more weight in the center. Depending on where the winch support is set and how the boat is loaded, I think 250llbs is in the range. If in doubt, run your tow vehicle over a truck scale without the boat, and then again with it. Junkyards and some moving companies also have them, or just search "Public Scales".
My C-26 is pretty balanced as it sits on the trailer empty. I pull mine with a K2500 HD and a ball mount without any drop so there is some weight on the tongue. If someone were to use a van with the same set up there would be negative tongue weight. I prefere to shift as much gear forward as I can just to gain weight on the ball to eliminate any sway.
Tongue weight will be much less on an incline. If you are going to put wheels on the front, and going down the ramp on a rope, the front might lift off of the ground.
I have watched many a Cat 25 and a Dana 24 with a front wheel and so far have not seen any problems. Am aware of the potential problem and will be watching closely.
Without the wheel I must put way too much of my truck in the water.