Hmm...not to brag or anything, but during my early weeks of learning guitar in mid-1972 it took me about 20 minutes to cleanly move between F and all the other chords I had learned. (Then again, I was taking lessons from—and was inspired by—a guy who was able to pretty much nail Jeff Beck's Blow by Blow album on third 3rd spin through the album)
20 minutes? Was that on a Strat with a .008 high E string and action so low a micrometer would be needed to measure it... or, say a cheaply-made acoustic with perhaps .013 (or higher) top string and action raised up enough to drop a cigarette through? Point remains: it involves contorting one's wrist and fingers into uncomfortable positions... and even your friend would probably concede that is every beginner's experience: barre chords and the 2nd-position B major type as dkmarsh rightly mentioned. [Yes... "Freeway Jam" was pretty much a requisite, and i also transcribed "Diamond Dust" myself (beautiful progression, not to mention George Martin's production), and covered it in one or two bands back in the day. Great stuff... definitely Beck's best.]
I'm not sure I follow the guitar chord simile, or would want to qualify it as a universally-applicable comparison. (Conversely, I used to touch-type at 70 wpm. My years of warehouse work made that skill disappear. I'm currently an eyes-on-keyboard pecker, but I'm a damned fast pecker! 
). Well, i'm not here to argue. If this device you made is any good it should (will?) pretty much sell itself.
Best o' luck.
