This is the one I use. 400mL and 180g. Its only good underneath covering or fibreglass as it dries quite brittle, but for this job its ideal.
FYI, since last weigh in I've glued on some extra balsa here and there, the wing fillets and done the surface filling and sanding over the whole airframe. This added a whopping........23g!! I think I can live with that.
regards Graham