57.5mm seems like a pretty good height, and fairly dead in the middle of the existing numbers out there that I know about:
- One builder used 63.5mm (i.e., 2.5 inches)
- Another builder went with 59mm
- And the sidewall height per the "Bandai 1/72 PG Falcon Conversion method" is 54.89mm (i.e., 55mm), by my own measurement and calculation.
What I would test, to make sure I'm happy with it, before committing, is how the 2" high forward mandibles look coming out of that 57.5mm high circle, and if that height gives you enough "lip" to overhang and hide the long Tamiya 1/35 M42 Duster greeblie (Part #A8) on the upper starboard mandible and still have the lip hover "above" that greeblie with some wiggle room to spare (see greeblie #5 on Parts Map MF018 1.2, pasted below). That's the precise point of reverse-engineering from the greeblies that I would try to test the theory of your sidewall height -- because it would only give you a scoche over 1/8 of an inch for that space, which may be enough as I have not measured the height of that greeblie. But there are lots of other considerations to keep in mind, like the height of your FalGal plates, Matilda plates, etc.
This is both the "trickiest" part of the build as far as I'm concerned, and also the most fun where you get to use "parts-to-the-whole" proper proportionality in your own artistic interpretation -- what I like is how, thanks to the durasteel plate overhang on the domes, the mandible sidewalls AND the dome sidewalls seem to be "visually" consistent in their height, even though they are not. So you want enough room to wiggle "downwards" with overhanging plating, but not so much that it looks cavernous once you get up close to inspect the sidewalls.
If you're willing to tell, I'd be keen to know how you derived the 57.5mm number, as I'm fairly obsessed with "build approaches" that different modelers take, and this is one of the most consequential decisions in the whole build, in my opinion.
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