Empress set Preparation.

someone else should be able to tell you the required dex with everything on, but to start, you need a good 170 dex and two slots without equips (where empress stuff will go)

Required dex with everything equipped is easy to calculate: highest total of stats required by the equip plus its secondary stats, not counting the set bonus.

For the VL set I believe that's the overall with ~26 dex requiring 170, which means 196 total. On account of this there's no point getting an above-avg dex overall unless you've got a higher dex equip somewhere else - if you had a 30 dex overall, you'd just need 200 total instead. ie. all other equips the same, the overall will cost more and not save you any requirements. But say you had a 35 dex helm, then that would be the main requirement (205) and the overall would have useful bonuses.