How to minimize damage from pitted cones?
I would recommend doing two things:

Reassemble the hub with the thickest grease you can find (within reason). It might slow you down a little, but it will help the bearings last as long as possible.

Make a mark on the back side of the cone that corresponds to where the damage is. When you're putting the wheel on, rotate the axle so that the damaged side of the cone is facing up. Then (assuming you adjusted the hub perfectly), there will be no pressure at all on the damaged side of the cone, and all the pressure on the good side.