If you are dowsing for gold, the solar angle is very important! I do best at dusk and dawn, because I am not fighting the solar magnetism, and just working with earth magnetism. There are three different magnetisms to adjust for;
1) Solar
2) Polar
3) Earth(ground)
Gold dowsing is a lot different than other dowsing, like water, etc.
I disclose the secret long ago on this forum.
And for depth, I just put my copper angle rods out in front and ask; "Is the depth between zero and three feet? Is the depth between three and five feet. A yes answer will cross the rods.
I also use traingulation when dowsing for caches.
I can discover theives and liars with dowsing. And spirits.