The 5.75 coils that work on the Tesoro Tejon and Cibola lose very little if any depth and really shine in trashy areas. Some of the small coils on other machines do seem to lose some depth though. I just bought a Cortes to go with my F75 and Tejon, I got a Troy 7" coil to use with the Cortes. I have not gotten it yet but have high expectations!
J
J