Excellent questions. You are correct, there is not enough documentation on this topic. I have been ignoring the weights and balance screen since the beginning because I don’t think it’s working correctly. My WACO YMF5 has spots for a pilot and 2 passengers, even though it’s a two-seater.
If I adjust fuel quantity, I can get the “red line” to appear, indicating (?) that the CG is not centered. But, the quantity of fuel required to get the red line seems random.
With all the trims in the neutral position, and without touching the CG screen, the model is very nose heavy at spawn.
I am going to play around with it some more (thanks for bringing it up) to see if I can get the model to be in trim at spawn.