I have a program called ASFD that shows values for many variables -- possibly it can help me with the center of gravity issues. What program are you referring to? I think you are right and that my model could use some improvement in that area. I will produce an update, but it may take a while.

With the spoilers, I just don't have any data to tell me how effective they should be.

Don't worry about your English.  It's a lot better than the French I have been trying to learn for decades now.