Enchanted Essence, every time.
There's a modifier now, for imbued items, when unraveling; it's reduced to 70% of the displayed value.
So, a 450 value imbued item, becomes 315, if all the properties were 1.0 weight.
If the properties were all 1.4 weight, the imbued item would be 225 after the reduction to 70%, so I don't think you can get residue from it.