For me I get most relic fragments from knights war cleaver made from gold ingots with copper or bronze hammer they need to be exeptional so +15 ash and over 20 exep talisman should give around 100% ex
true only gives 2hpr knights gives 3 hpr
Because of the diminishing multiplier that applies when you use gold ingots to make the knights war cleaver, your yield is the same using dull copper ingots.

Valorite yield is best, but I prefer not to burn through those if I can.
I've tested the true war cleaver now as well. Only way to get 90%+ back from those is to use Val ingots, but they are still a great source.
I believe I finally have all of the information that I've been looking for regarding unraveling, so I've been toying with my spreadsheet as I've had time. The negative multiplier for items with over 5 properties is a serious pain, but it looks like the racial and queen's forge bonus's can make up for a good portion of what you lose. It's looking like there will be quite a few other options for those of us that make relics with hammers and gems.