I don't worry about how much weight is on the DFW when setting my cars up. Put the car on the track and adjust the weight until you get your fastest times.
If you must know how much weight is on the DFW, you need to use three scales, one for each wheel. I have no idea what mine are, nor do I care. I'm not buying two more scales, one's enough. Every car is different.
Some times I think that a lot of people try to get to technical on these cars. There are far to many variables while trying to get some of these technicalities right. Stacked tolerances will play havoc on your science. /images/boards/smilies/smile.gif