Any ideas on a good cg location for the Sky Angel Mig-15?

[earthsciteach]

I flew the 50 mm Mig for the first time, yesterday. Winds were 15-25 mph, so I couldn't get a good feel for it, but it seems to be tail heavy with the cg at the recommended 9.5 cm from leading edge at the ring root. I see many comments on adding weight to the nose of the Mig on RC groups, but no specifics on how much with the stock motor/fan/battery.
Thanks!