No. Build it just like the the guy shows in the drawing. Orifice(damper as he calls it) is between regulator and gauge that you take the reading from.
The reason for having a second gauge on the regulator is for a more accurate reading. After you make the connection and the air is escaping through the burnt valves or broken rings, the pressure on the supply side of the orifice may blead off a little below 100. You adjust that back to 100 even and the reading on the other (100psi) gauge will represent a more accurate % leak. The single gauge unit will work just fine. Just not quite as accurate.
I took another look at that setup in the photo(that I posted) and read his write up again. I had assumed that the pipe nipple between the quick connect and the regulator was an epoxy filled orifice like the other guy had. Wrong. He makes no mention of it. He is using the restriction in the hoses and connectors between the compressor and his test unit for the pressure differential. He is setting the compressor supply at 100psi. Pressure is lost in the supply hose and the regulator on his tester can't regulate what it doesn't have so you get a reading on the gauge showing the pressure loss in the hose. If he uses a different supply hose that is shorter, longer, smaller, he would get a different reading on the same cylinder.
