Hi, I am a little confused on where you are measuring from and to. Can you provide a sketch showing a typical vehicle wheel loaded on to the trailer.
The 6600-lbs is based on what?
Is that the max rated load?
Do you have any pics or websites of an actual trailer you are trying to emulate?
If the loaded-vehicle wheels are positioned behind the trailer wheels, I can't see how you will ever get a positive weight at the hitch end. Maybe I am not understanding what you are trying to do and a few pics of an actual trailer would help immensely.