Hi John. I'm sure someone has a chart started for you, but making your own is an easy one hour project for common targets. The trouble with VDI charts is that they will vary somewhat with ground conditions and locality, they are also not reliable, especially with targets at depth, wear, orientation, multiple targets, targets next to trash etc. Air testing for a VDI is often not the same as a "seasoned" deep target and if you like to dig gold rings, they can be anywhere on the VDI scale from 35 to 70 depending on the size, orientation and purity, silver rings from 70 to 90. The VDI is just a tool to help you guess what the target MIGHT be, good or bad and experienced hunters will often gather more valuable information from how the VDI is reacting to a deep target and not so much what the numbers are. I wouldn't put put a lot of faith in a chart.