Well, thanks everyone. Especially the guy who PM'd me with data about his, and Russell, who not only provided the data I wanted but a disassembled look at the innards, too.
I'm hoping to incorporate a feature not found in commercial quadrants. I don't expect to save money but if I do, so much the better. I'm building an RV-3B more for the project than to have one, and the quadrant might make a nice part of the project. As I see it, since once in a while there's a hiatus while I'm waiting for something to happen (a machinist to finish something, epoxy to cure, parts to arrive, whatever), this will make a satisfactory fill-in task while giving me something I want anyway.
I already have all the device throw lengths from the carb and governor; thanks for reminding me about the governor, Axel. And I have comparative cockpit control movement distances from my C180, along with an idea of what I'd like to see carried over or changed with the RV-3B.
Michael, it was your quadrants that started me thinking about this. Yes, of course mine will need to be individually designed to suit, especially so for an RV-3B. In this thread I was simply hoping for an idea of the basic geometry of the commercial quadrants, more for comparison than from any plan to copy them.
Thanks again, and if anyone has similar data for any of the other brands of quadrant, I'd sure like to get it.
Dave