In order to gauge the proper position for the washer pump on the left, I removed one of the horns, lined up the washer pump and marked the spot. The right side is easier to mark. Drill gently with a 7/8" bit and wash out the debris when done.

I had to remove the pump on the left to install the reservoir as it blocked the mounting hole. Once the reservoir was installed, I slipped the pump back into place, reconnected the hose and electrical connectors to both pumps. Finally, the horn was reattached.