RPM step size

Hi,

I am creating a RPM controller for my spindle. I can change the rpm with 2 buttons. What steps size would you recommended? 100 RPM would be too low and a pain in the … to go from low to high. What is a good compromise? step size of 500 RPM? 1000 RPM? How precise should it be?

thanks!

I will post my solution when its finished