[Punisher454]

Yes thats about the launch tube length I have. The main difference is the inclination towards the bow of the ship. If we follow the filming miniature the launchbays angle at about 45 degrees forwards. The live action set was around 22 degrees forward.

I tried building a launching bay section at 45 degrees and it looked terrible. Very little resemblance to the set which receives so much on screen time. The launchtube exits on the other hand are never shown very close up and get a very small percentage of on-screen time, furthermore the angular change does not look that much different on the exterior model.
Also the 45 degree angled tubes dont work out to be much longer than the shorter tubes.