Measuring for a Bottoms Up countertop dispenser hole

Countertop dispensers only require one, four-inch hole to run all tubing through. But, where should the hole go?
If your bar or counter is made of a material other than wood (or something easy to cut), you or a third-party will need to cut the hole ahead of our arrival.
Here's a guide to measuring the placement of the four-inch hole with a couple different dispenser setups.
0:20 Countertop dispenser overview
0:40 Chassis measurements
1:33 Measuring the dispenser to be flush with server-side edge
3:45 Measuring the dispenser with a bar mat in front of it
5:00 Mirrored dispensers
6:29 Why you need space between the mirrored dispensers
7:30 Measuring the space for mirrored dispensers
10:10 Leaving room for tap displays
10:52 Side-by-side dispensers
12:09 Leaving space between the side-by-side dispensers