Re: VDI FOR RINGS DFX 300??
Now that's a tuff order. Rings, depending on size and makeup can cover the entire range you mentioned. If you decide to skip targets you think could be a pull tab then you will chance missing a ring. You might really be interested in the book, "DFX Gold Methods" by Clive Clynick, it is a great resource on the topic.
You mentioned that you are using the Coin & Jewelry program. Have you tried increasing your Preamp to 3 or 4 and your AC Sensitivity to 70 - 75? These settings will give you a nice boost in depth. Another thing you could try is hunting in all-metal mode (toggle switch locked forward) until you get a target signal, then pull and release the trigger to go back to motion mode to check the VDI of the target. All-metal mode will normally give you more depth than motion mode.
Re: VDI FOR RINGS DFX 300??
Well there is sadly no way around that digging that I am aware about.
The one gold that I found rang in around 10-20. (air test)
But as some one said: "Location, location, location..."
A beach is a great place to try your luck, especially if you can go into the shallow water.
Easier to loose your ring, with all that stuff around; i.e. slippery skin, water and so on.