To locate the balance point, here's a good calculator:

http://www.geistware.com/rcmodeling/cg_super_calc.htm

Just fill in the blanks and you'll be OK. Works for almost any model you can possibly build.

For control throws, if you start out with about +/- 25 degrees of control movement as a maximum, with about 30%-40% exponential (-30% to -40% with Futaba systems), you'll have it about right. Fine-tune it from there.