Thanks Matt, just wondered if it would be a viable solution to the problem! clearly it is but at the cost of extra weight........Mmmmmm.
If you completed this model with the elevator servo/s in the cockpit area of the fuselage, the extra weight would not be that much of an issue in terms of achieving the reqd c/g.
Derek, sorry for mis-understanding your request, I simply mixed up the resin/balloons to a thickness that would not just run of the formers, thus allowing enough time to locate and place the formers in their final positions

Kind Regards,

Andy.