My experience / opinions:
My Cibola (Vaquero should be very similar) has threshold usable for pinpointing at about 12:00. Super tuned at more than a threshold at between 1 and 2 o'clock and iron is not discriminated out very well. The higher the super tuning (higher threshold setting) the more discrimination is lost on iron. Iron bigger than small nails starts sounding very sweet and even some of the small nails sound too smooth to leave in the ground.
Running the 12x10 widescan (DD) coil super tuned, I might just as well dig it all. The widescan coils do not discriminate as well as the concentric coils on these detectors. I have not tried the SEF but am thinking it may act like the widescans with respect to the discrimination. Have you compared it to the standard coil with similar settings on the same targets?
For one way signals, the only way to really tell if you are uncovering a good, partly masked target or responding to an edge of an irregularly shaped piece of iron is to dig it.
Tejon does not seem to gain much depth or loose much discrimination by super tuning, just don't have a usable threshold so there is not much point in super tuning with the Tejon.
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