I had to put 3 lbs into the nose of my Balsa USA 1/4 scale Fokker DVII. I built two boxes of balsa, poured in a mix of 2 1/2 lbs of lead shot and 8 oz. of epoxy. ( 4 oz of each of course ) When the epoxy set I had two weights that I could put anywhere I needed to get the CG just right. The lead shot I got at the local gun shop. I think the plane you are building is going to handle the weight just fine.