Gauge rebuilding

[Dave Page]

Hi Guys,
I am calling upon the collective knowledge of gauge rebuilding expertise, namely for a Jaeger 2" water temp gauge. The gauge is currently fitted and functioning correctly but I wish to change the needle/pointer to a different type. My questions are: how difficult is this to do without buggering up everything? What should I do/not do? Or is it just best well enough left alone.
Cheers,
Dave