American Powertrain Hydraulic Throwout Bearing Kit Questions

We have purchased an American Powertrain hydraulic throwout bearing kit to install when we convert my son's '68 Dart from 727 auto to 833 4-speed. Anyone have any pictures of this kit installed ? How far down on the clutch pedal should we mount the master cylinder ? I've seen other threads that say 2-3/8 inches. Any recommendations, do's or don'ts from anyone who's already done this..??

Thanks in advance.

Mark.