David,
.035 sounds like it used the 12V set up. .025 would make sense although I don’t have my manuals here to check it.

A simple explanation.:
The ignition system is designed to make a spark at a set time relative to piston motion in order to initiate combustion. The timing of this spark is controlled by the position of the dizzy and its amperage. (Ability to build potential on the plug electrode.) If you still run points then there are some other factors such as points gap and dwell that have an effect. The spark will jump the gap when the potential exceeds the dielectric (Air gap). This potential has to be rebuilt every two engine revolutions in a 4 stroke cycle. The amperage of the dizzy dictates how quickly the potential can be built. A 24V system has lower amperage than a 12V so takes longer. In order to have the spark jump at the right time you close the gap so that less potential is required. I am no expert on combustion but it is my understanding that it is spark intensity and not size that is the important thing so the actual gap being reduced does not less performance. Someone will no doubt chime in with more detail/better explanation.

Having said all that if it is working and emissions are good I wouldn't mess with it. The last 5 minute tune up I did turned into a 1 1/2 year rebuild. Damn the shipfitter's disease. Still it does mean that I have her stripped down to the roll hoop and spare while I bed the engine in. The 101 is the most fun convertible I've ever driven.

The beauty of converting to a 12V system is that you can ditch the points and ballast resistor and replace them with an electronic ignition and sport coil. I say this only because I have not seen a 24V equivalent. This gives an almost maintenance free system (rotor and cap occasionally) with a more consistent spark as there is no mechanical wear/adjustment in the points. In theory you will have a faster ramping system with the ability to develop more potential in a shorter time thus allowing you to increase the air gap for a fatter spark and higher performance. In reality we are driving an army truck so any gain here most likely is not noticeable. I keep mine at the stock setting.

Contrary to some opinions electronic ignition is reliable. There is some infant mortality due to manufacturing errors but, generally, if it works in the beginning it will work for a long time. For justification, look at the number of posts regarding issues with points ignition vs electronic.

Cheers
Gregor