I agree, raw theory is a good starting point, it's better then nothing at all. I'm always fiddling with different configurations, both in scale and design and find some pretty neat results at times. With new pilots, I tend to tell them to place it forward of the reccomended COG, this helps them with stablity, as you stated, but it's also fun to place it slightly aft, you get to really push the envelope as to what acrobatics you are able to pull off that would be more difficult if it was dead on. Then you get into 3d land where it's rarely set for stability and unpowered, tend not to glide so well.