Hi,
Gear ratios look fine for your setup.
The telescope going way too far suggests that the microstepping mode is going wrong somewhere.
Which drivers are you using? Have you checked all the solder joints for the MSx pins on the drivers, and the MCU socket - a dry joint could cause the wrong mode to be selected resulting in in driving too far.
Also, what microstepping mode have you selected in the config? Could you try picking something like half-stepping initially, just to test things out. You can then increase the level for better accuracy once working.
Kind Regards,
Tom.