No, the radio gear is not fitted yet. For filler I was going to use wood glue mixed with balsa dust because i'm going to cover the wings in transparent film and the wood glue mixed with balsa dust will hopefully be the same colour as the balsa and not show up through the film. I think Polyfilla is white, but i may be wrong. Only problem is that i think wood glue mixed with balsa dust is not that easy to sand.