Thanks all - I did see people using them but just wondered if there was something I'd missed before using standard bits. Seems like a really obvious question now:)
The stepper drivers were set by default at 1000 according to switches so have changed the switches to 1600 in the table as recommended.
I was thinking the "units" referred to cm - as UCCNC defaulted to 200 steps per unit, I took this as meaning 200 steps @ 1.8 degrees to make 1 revolution which would equate to 10mm of motion, so a unit being 10mm. I guess I was calculating the wrong way round!
Does jogging use the same velocity settings - as jogging seemed to be about 10m/min which seems about right , even with microstepping on drivers set to 1000 and steps /unit at 200?
With the hybrid steppers I mean that many build logs on here and other forums use "standard" steppers without an encoder, and wasn't sure if mine having encoders that had any bearing on the tuning. Assuming it being a closed loop the controller never knows any different anyway.
Once I get the replacement ballscrew and right size drag chain I'll do some more testing and tuning.