I think you are using a very good coin machine, personally.
I have a golden umax, a silver umax, and a Tejon. The silver is an excellent coin machine, that really likes the deep dimes for some reason, at least mine does. My Golden had the 4 tones, but I generally only use three of them (disc out the iron). I have found myself lately setting the disc as low as I can without picking up iron, and digging everything. I am finding more nickels now, but I am also digging more pulltabs and other junk as well. The golden is my favorite coin machine for hunting the parks and playgrounds, especially with the notch feature....which takes some practice and getting used to, but it really does work and it is helpful. My Tejon...it is very sensitive, and deeper than the other two, so I have to be more careful about what I dig with it, as I found myself with a 9 inch hole at the local park real quick like...and I did get the quarter, but I am not a fan of going that far down in the parks.....but that's just me. I have also found jewelry with my Tejon, due to the fact that I run my disc very low(prior owner setpoints

) and I dig everything, as I am still in learning mode with it, and probably will be for quite some time.
I have never hunted with a Vaquero, so I cant offer an opinion on them other than the reviews that I have read and the things that other folks say about them on these forums. Your depth should be on par, or very near the Tejon for coins, which is greater than the silver and the golden umax's plus you have ground balance option on yours which will definitely help in hunting different types of ground.
Have you considered the Cortes or the DeLeon? They have the TID screens if that might be what you are looking for?
LittleJohn
LittleJohn