Problem is, we don't even get to see the item property values.

Before you see them you have to select the property to imbue. Then it tells you "You cannot imbue this item with any more properties." So, we don't get to see the property weight calculation for artifact this way.
You also can't seem to change an existing property e.g. physical resist, if the number of properties exceeds 5, which is for most artifacts.
Also, imbuing luck on a 40 luck spined leather piece overrides the luck value. It doesn't add up. So, no changes here.