determining pay load capacity

Yes, 2744 is your capacity. The general rule of thumb is to look at the gross vehicle weight of the RV, not the empty weight, of the RV you are looking at and take 25% of that. That would be the pin weight that would count against your truck capacity. So a 10000 lb x .25 equals 2500 lbs. That only leaves you 244 lbs for your hitch, passenger, dog, etc. I believe 2744 already includes a full tank of gas and a 150 lb driver on a 2015 model. Most 5th wheel hitches will be in the 150lb range except for the Andersen hitch. You can read up on it. People either hate it or love it. I have always used a B&W hitch which weighs close to 200 lbs. Many folks will tell you to disregard the yellow sticker and look at the rear axle capacity and as long as you don't exceed it or the tire capacity you will be OK. 2744 lbs seems low for an F350 with a gas motor.