These 1936 installation instructions will give you a couple of the measurement you're seeking. I'm in the slow process (it's been over a year) of building a 1/6 scale model using the 12" repro signs.
You'll have to print these and then tape them together to read it.
I used these instruction to install a full sized sign at my place when I lived in Wisconsin. (you know, where the SUPER BOWL CHAMPIONS are from !)
That last part is for Mick.





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