Not sure on the cg thing, although I have flown wings too and that does not sound like a bad starting point.


I think the amount of ballast you need is dependent on many factors and does not need to be perfect unless you are trying to break records. Wind speed would be the primary factor. Adding ballast causes the plane to fly faster at a given glide angle. It will also increase its sink rate. If you over ballast, then you will not be able to stay up easily. If you under ballast, you may have a wind penetration issue ( I doubt this on a real slope machine though).