Here's a set from an aircraft in my hangar that doesn't actually have floats but it is set up so that you can skim the water with it's tundra tires:
//float
point.7 =4, 0.95, 2.75, -4.55, 4200, 0, 0, 0.0, 0.3, 2.5, 0.90, 0.0, 0.0, 3, 0, 0
point.8 =4, 0.95, -2.75, -4.55, 4200, 0, 0, 0.0, 0.3, 2.5, 0.90, 0.0, 0.0, 3, 0, 0
point.9 =4, -1.0, 17.0, 1.90, 1600, 0, 0, 0.0, 0.0, 0.0, 0.00, 0.0, 0.0, 5, 0, 0
point.10=4, -1.0, -17.0, 1.90, 1600, 0, 0, 0.0, 0.0, 0.0, 0.00, 0.0, 0.0, 5, 0, 0
You will have to make the 'point.n' numbers match the sequence in your config files (just add the above to the end of your [contact points] section).
If you are not sure what all the number groups represent here's the contact point section from the online ESP SDK (it's the same as the FSX SDK):
https://msdn.microsoft.com/en-us/librar ... ocId836373
That explains what each number group controls and distances are all in feet, measured from the aircraft datum point. Note too that you need four float points to keep an aircraft/helicopter level on the water not three in the wheel locations.
I'd suggest adding the points I posted to any helicopter you like, test and then adjust the values until you are happy with the results. There is no easy way I'm afraid as it's all trial and error (even for developers!)
Here's another tip too. If you don't already have it assigned go into your controls options in the sim and set up a key command for 'Aircraft (reload)', it's not set by default (I use CTRL+SHIFT+R ). Then when you have edited the contact points save the aircraft.cfg file but keep it open, switch to FSX and hit your 'Aircraft (reload)' key(s) several times (you need to do this to be sure it has actually fully reloaded) then check how the helicopter sits on/in the water. Repeat the edit/save/reload steps as many times as required.
Reloading the aircraft that way will save you a lot of time over closing the sim and restarting each time you make an edit.