It is always best to take advantage of your metal detectors best feature, which is normally the search mode.
If you search the beach with a discriminating VLF metal detector, use the discrimination.
Using your discriminating metal detector in the all metals mode all the time, defeats the purpose of having a discriminating metal detector.
Reverse hunting is exactly that, metal detecting in reverse and wasting valuable metal detecting time constantly having to stop and double check targets.
Buy a pulse induction metal detector if you want to dig all metal targets.
The same applies to beach and water hunters who use a pulse machine and try discriminating with a pulse induction metal detector.
There is absolutely no way to make sure you are just skipping bobby pins by ignoring targets giving off a double blips type signal. Large gold rings and bangle bracelets give off double blips.
You are at a disadvantage, the minute you start searching the beach without using the best feature(s) on your metal detector.
Some discriminating metal detectors hardly have a difference in depth between search modes.
If I switch to the all metal mode when using my CTX 3030 or Excalibur II, it is not for added depth.
It is to cancel the effects of iron masking, by taking out as many ferrous targets on a productive site as possible.
I then use my CTX 3030 or Excalibur II to do what they do best, sort through the trash to find the treasure.