I have a request; I've been working on this for myself, but it should be pretty easy to add to the baseline (it's a little bit of work for me to have to do it with each release of the sheet as it requires me to edit the Lookup Sort macro):
An "Upgrade" column in the Lookup sheet, that will VLOOKUP whatever item you're currently wearing, and then list how much SEP difference there is between the two. This will help identify where the largest upgrades are without having to manually do the math.
Insert a new column at Lookup!T_, heading "Upgrade".
T2=M2-VLOOKUP('Set1'!$B$6,$D$2:$O$234,10,FALSE)
Fill down. Repeat for each slot.
Then, when you click sort, I can see that getting the Obsidian Greathelm is 50SEP upgrade, and Collar of Dissolution is 25SEP, etc.
The reason why I found it necessary to do this multiple times rather than just once is that SEP values can vary dramatically with upgrades. I did all the work manually yesterday, then got a few upgrades and it really changes my plan a lot.
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Edit:
Just a note if you want to pursue this: you'll have to update the SEP macro as well in the weapon speed SEP calculations. Add +11 to the columns for main-hand, and +12 to the columns for off-hand. This is in addition to the LookupSort changes that would need to be made. If you want, I can send you the macros I'm using and/or the whole sheet (which includes the Upgrade column for every slot). Just PM me or reply here