G'day Mate,
Are you sure it didn't have a CG (balance point) in the manual, it should be towards the end of the manual, possibly inside the back page, it may be in the same section that shows control throws.
If that is the CMPro ARF, 58" span, the CG (balance point) is 80 to 85mm back from the leading edge of the wing. I have put 5 CMPro ARF's together, & they always have the CG, or balance point in the manual, somewhere.
If it the other one, 55" span, whatever brand it is, I'm still betting it is in the manual somewhere.
If you can't find it, use this calculator, to help with your CG, keep it in your favourites, it may be useful later on.
http://www.palosrc.com/instructors/cg.htm