Nice job.
I have two questions regarding the installation.
Do you have openings for ais cooling in the case?
Dit you install a extra RPM meter in your drill?
I made a similar installation with a VFD in a drilling machine, the spindle was driven by a belt 1:1, so the spinle hat the same spped as the motor. So I removed the control box from the VFD and installed the controller in the front panel. The conection was solved by a extension cable of a leght of 10 inches. I used only a safety switch for emergency stop, which can barke the motor instandly.