An alternative would be to purchase an engine pre-luber (or preluber).

These are common on commercial engines (trucks, stationary engines) and race cars.

The systems are about $150, which sounds pricey. But, if you figure that you are using your starter motor at, at least, three- or four-times (closer to five-to-ten probably) it's normal duty cycle, then the $150 investment compairs favorably to the cost of a starter motor.

These systems typically involve an electric pump, which pressurizes your lubrication system BEFORE your engine starts turning. This is THE hot ticket, because your idea still causes your engine to turn, without oil pressure and against compression.

Instead of electrics, some systems use pneumatics. Some systems use hydraulics.

Instead of a separate switch for the pre-luber, you can probably wire it in to the ignition circuit so that it comes on at the key position where the ignition is on, but not the starter. Whenever you are starting the car, turn the key to that position, and leave it there for a few moments. Then, start the car.