For me parking to Home Position from SGP works with Losmandy G11 and Gemini 1 Level 4.
For some reason the ASCOM driver doesn’t have an option to set the Home Position, you must do it with the Gemini Handset.
If you set a park position via ASCOM (e.g. by pressing Set Park in SGP’s Control Panel), the driver will remember the Alt/Az coordinates and slew to them before parking. However, the exact position depends on the exact sync. To get a repeatable park position, you must set Slew Home before Parking in the ASCOM driver settings instead of the Alt/Az coordinates, and never use Set Park in SGP.