Awesome! Your mission statement couldn't have been put any better. As far as axle placement: It needs to be as compact as possible, yet the cog can't be behind the axle(making it tippy) so a lil trial and error may be in order to make it as small as possible yet stable. PM me if you need anything, I am your sounding board!
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It's "Dr. _paralyzed_" actually. Not like with a PhD, but Doctor like in Dr. Pepper.