It appears that your geographical location would use ICAO standards.
Obstacle clearance and other factor would depend on what operational level of flight is to be used. Doubt if one should try an IFR approval for the procedures.
It is likely this will be a visual approach, so that will dictate the obstacle clearance areas, and minimum requirements.
In many mountainous regions, a spiral down approach is required to meet aircraft performance levels. As it is mountainous, (and private) one should probably look at a missed approach procedure as part of the design...
As this appears to be a private airstrip, there may also be exemptions that can be applied for.
Nor really necessary to use a concrete runway for a small jet...unless there are adverse soil conditions..
Good luck