Dwell is an over rated spec. It was usefull on old multi cylinder engines because it allowed you to average the point gap to compensate for worn distributors.
If you conside the length of time the points are closed at 1000 rpm and 5000 rpm, small changes in dwell pale by comparison.
Having said that, the relationship between the energizer coil, the flywheel magnet and the points opening, is designed into the magneto and if you change the timing too much, you will loose spark energy.
I guess if I were to do it, I would compare spark before and after.