Hi Matthew
The GPDX is values are +036x144 for both RA and DEC, where 36 is the gear ratio of the motor gear, and 144 is the gear ratio of the worm gear.
From my SS2K manual:
The worm gear ratio is also used in the PEC computation. The sign of the gear ratio represents the direction of rotation of the final gear. The default values for the parameters in this menu are set to the values for GP and SP equatorial mounts. The values may be changed if other mounts are used. For GP and SP mounts, please do not change the default values.
The change from +ve (default) to -ve (Atlux) for the gear ratios between the GPDX and Atlux settings
were what caused Gerald quite a lot of grief recently.
Cheers
Dennis