Designing my first CNC, any ideas/answers would be appreciated: [1]Looking to move XY stage with fine resolution: 5 micrometers [2]The stage will only need to

Designing my first CNC, any ideas/answers would be appreciated: [1]Looking to move XY stage with fine resolution: 5 micrometers [2]The stage will only need to support ~5grams [3] There will be optical feedback [4] speed can always be sacrificed for accuracy - Instead of the classic steppermotor setup, I was wondering about the feasibility of servos with arbitrarily reduced gearing (let's say a stack of laser cut planetary gears). -What are the pitfalls of this method? has anyone else done something similar?