Geo, the background is fine for judging. It's a good neutral colour and the odd variance in the background is no big deal. I was commenting mainly on the fact that you obviously took the time to make sure things line up perfectly in the front and back shots. It's amazing how often a twelve o'clock view shows up as 11 or 1 o'clock in the finished pics and the same goes for the six. I use these shots to judge symmetry of the build, looking at the undercarriage, ordnance (if any) and wing alignments to see that these are all correct and too often this is made very difficult.
Good luck on the 29!