You have to work out your own salvation with fear and trembling....
So for each subassembly, there's always the question of the measurements, and you can either a.) trust someone you ask, b.) go with somebody's blueprints, or c.) figure out yourself. I typically choose d.) all of the above, in comparison to the neighboring greeblies, in order to see what looks perfect.
So on this turret ring, there are two schools of thought:
A.) 12" base, with 11.5" upper ring
B.) 11.5" base, with 11.0" upper ring
C.) Maruska's drawings, which favor B.
D.) My non-computerized, non-algorithmic interpretation of the Japanese Star Wars Chronicles book pictures of the 5-footer Falcon, using their rulers in the picture as the ruler to apply to the rest of picture, actually gets you closer to somewhere between 10-3/4" and 10-7/8" for the upper ring. IF (big if) this was a one-piece disk that was trimmed down on a circular lathe, then it would make sense to have the bottom be a clean 11.5 and the top be whatever was left after all the angular trimming. That's the way I'm currently leaning in my interpretation, and without a lathe, I am trying to basically have "all options" on the table so that when I get to placing this on, I can make a definitive judgment of which one looks/fits best in relation to the side docking tunnels, the front jawbox, and the rear engine deck.
So long story short, what you're seeing on the picture is a combination of a.) Glowforge lasercut rings, b.) Shapeways versions of the ring turret, and c.) a big fat 12" ring that is now categorically "off the table" unless and until the overall geometry proves otherwise.
Part of how I judge/assess/discern this is to try and get inside the head of Joe Johnston, the original designer, and the other builders at ILM. Johnston had a wonderfully "asymmetrical symmetry" pattern for most of his designs, and on the Falcon this is worthy of its own separate (coming soon) post. But one thing it meant was that the front mandibles had an outer dimension (from outside left to outside right) of 11.5", which would have been visually "balanced" by an 11.5 bottom ring, tapered down to whatever was left after the lathe did it's work. But if I'm wrong on the lathe approach to the turret ring, then it's entirely possible that it was a 12" ring at bottom that was tapered down to 11.5" on top in order to achieve this same symmetry between front and center of the ship. This is how Lee Malone built his, and it looks amazing. Sean Sides did 11.5 on bottom and 11.0" on top, and his also looks amazing. So again, it's a parts-to-the whole and a "work out your own salvation with fear and trembling" approach that MUST be taken because in the end, only you have to live with the end result of what you've decided.
In no case should you let someone else "do the work for you" and "trust their judgment" simply because they've done it first. You have to be happy with the ship you've built, and you have to own your own work. Or at least, that's my philosophy, one reason I'm still not happy with the Y-Wing armature, and still working with a colleague in CAD to perfect that substructure.
