Guide camera
I own a ZWO 120 MM, but was testing a friend's ZWO 290 MM and I can't remember which one I was using that night.
Image Scale
If you mean FL ratio then the Esprit 120 has a FL of 840 plus a bit more with the 1.01 flattener.
The guide scope is a Baader Vario with a 60 ml objective and 250 ml FL so around 3.4 : 1
https://www.baader-planetarium.com/e...0x60-3069.html
Guiding
No dark calibration, 2 second exposures, multistar guiding with ASIAir plus
Cheers
Paul