We already have a very nice handlebar unit with a reset button, in the form of the electronic counter.
I prefer the non-reset Jones version for recording the data, as the continuous string of data tells a story.
One example - with non-reset, if a measurer does all his calibrations in one direction, because he is afraid of traffic, this will be seen from the data. It's not common, but it happens.
As for counter configuration, the present general layout is robust and has proven successful. If the brass threaded portion is eliminated, to make assembly easier, a flexible shaft drive won't fit on it.
Gear ratio using the present gearing yields 23.636363..... counts per revolution of the bike wheel, and the matchup of the gear teeth is good - better than the original which has 20 counts per revolution. A round number here is not important.