This trick will let you bump your expertise for a slot up by quite a bit using fewer Umbral Shards than usual.
Once you hit 600 GS in a slot, you can then upgrade using Umbral Shards. If you put a Named Item in a slot, say a 610 Great Axe like in the video, and upgrade it 1 level using the Umbral Shards, your Expertise for that slot will jump from 600 to what you just upgraded.
