I did my first barrel swap with just the GO gauge. I put in the chamber, tightened the barrel down until it stopped, but did not "over turn it in". Then I cranked the nut tight. I measured the GO gauge with my micrometer, put one piece of tape on and measured it again, once in the same spot and once turned 90 degrees to be sure no major thickness variation. This got me to barely 0.002" more. I put another on and did the same thing, giving me a total of a shade under 0.004" (which I have read is around the NO-GO gauge difference, but this seemed to depend on the manufacturer). I slid it into the chamber and the bolt would not close. In fact the bolt handle was in the exact position as the one in the video demonstrating the tape technique.

DISCLAIMER: tape thicknesses can change, trust me, I know. I use and see alot of tape at 3M (work). SO PLEASE MEASURE BEFORE AND AFTER TAPE ADDITION!!!