A few questions: 3:1 ratio okay for accuracy? is my setup correct?

A few questions: 3:1 ratio okay for accuracy? is my setup correct?

1)I am running a 3:1 ratio for my servos, will this have an effect on
accuracy since my step increment will be .00033333333 inches and is
not a nice even number such as .0001 or even .0005.

2)I have no idea of the "Steps per Rev" of my motor. I just played
with different numbers until "100" gave me the motion I wanted.

I also played with the "Microstepping" input as well, so I am not
sure which number is correct or if I was just lucky.

This is my setup:
Steps per rev: 100
TPI of screw: 5
Microstepping: 2
Reduction: 3

Motors are Litton 420oz brush DC servos (bought from Camtronics many
moons ago)

I did spin the motor manually and counted 22 "detents"...does this
mean anything? I'd like to be as accuate as possible with my setup
and I am not sure if 100 SPR is okay or not, just 'cause it works,
does not mean it's correct....

I'm running Gecko 340's as well.

Thanks