Only ever got one ride in a Chippy, long before I was clever enough to be able to tell the difference between a bag of bolts and a bolt of lightning! Couldn't see from the back seat.
I'm sure there are rules of thumb for "fag packet" design, found this:
http://www.aircraftdesign.com/newcrs.html on a google search under aircraft design.
I don't design them I just try and fly them and pass on my thoughts! Strictly the sizing of the controls relates more to control power in the first case and the harmony bit comes as a by-product.
Tarnished