Just for comparison - the Mag 52 FS weighs 15.5 oz and an OS 46 LA weighs 12.0 oz. Little things like this might give you a hint that there might be some balancing issues when you build it by the book.

Really hope that this is not your only kit. I'm on my 7th or 9th or something. I keep running into things that affect the balance - like really heavy stock used for the stab & fin. Didn't think much about it until I had to add a bunch of weight to the nose. I've rebuilt it and the added weight is history. If I only knew then what I know now ...

Em, how about adding a pilot? A chubby pilot.