RB - perhaps a screenshot of your project could help us understand better where you are and where you want to go.
Sometimes, and I'm as guilty as anyone else, what is "obvious" to us, is not as clear cut to someone else.
For example, when using FSDS, *I* know that on first compile, FSDS will read the contact points from the reference parts (gear.left, gear.center, gear.right) and write those values into the new model's aircraft.cfg file. FSDS "reads" the aircraft.cfg file from the "seed/reference" model, copies it to the new model's folder and rewrites the contact points in the new model's aircraft.cfg file.
HOWEVER, I also know that the reference parts only read the WHEELED contact points.
For float type contact points, I would create reference parts for the appropriate contact points - I would name them float.FR, float.FL, float.RR, float.RL (FrontRight, FrontLeft, RearRight, RearLeft, respectively).
When compiling for the first time, and assuming that I've used the float plane Caravan, or similar as a reference, I would not immediately go to FS-X, but rather open up the refparts.txt file that has been generated in the FSDS folder, and see the coordinates for my float contact points.
I would apply those values to the appropriate contact point references in the new model's aircraft.cfg.
Sorry for the short explanation, but I'm at work and cannot create a quick "Lionheart style" tutorial at the moment.