I went with Pos Neg Neg which gave +6 con, existential stalement so +6 wis (the +10 haggle is kind of nice as well), and the +1 exceptional int and +2 exceptional int.
This combo frees up a slot for +6 con item (for like you I will use the napkin for the +6 int) and adds +3 to my will saves. In the belt slot I then went with the belt of the seven ideals with improved potency VII (which is ok, I usually use a superior potency VI item) and spell penetration VII on it as well. Lots of ways to go here! Have fun crafting all.