[Jack21]

If you plan on driving the car in the rain, and/or getting the car inspected, you really do need two wipers. The wiper blades are only 10" long and barely do the job using the pair of them.

If neither of these apply, omit the wipers alltogether. You're not accomplishing anything with one wiper blade, even if you put it on the drivers side. And less if you put it in the middle.