A sewing needle may work for a splint. Experiment with adhesives. Extra weight near the center probably won't affect the speedo.
The break may be visable though the odometer window. But the needle is thin and painted flat black at that end, so it will disappear against the odo numbers.
I'm sure that other 'Bolters have had the same problem. Perhaps they can add some experienced advice. I'm sure that all will be interested in your fix.
Don't know if you are going to reface your gauges -
> Here is a thread of how I did mine> Slide show> Album- Lonnie
