I am hardly an expert, however there is a Kindle book on amazon for the Vaquaro and Tejon... Sandman will chime in soon with the link!
I run my Tejon to blank foil to get nickels and gold too.. The GB set -1/8-1/4 turn and sens as high as it will go without a lot of falsing...
If you want to high grade dimes and quarters and run to chirp on pennies and pull tabs you may loose a half inch or so according to the book! Or just learn to thumb the disc knob!
Excal 1000, Excal II, Sovereign GT, CZ-20, Tiger Shark, Tejon, GTI 1500, Surfmaster Pulse, CZ6a, DFX, AT PRO, Fisher 1235, Surf PI Pro, 1280-X, many more because I enjoy learning them. New Garrett Ca