I do not reduce the superfat when using milk. It would be hard to figure what percent the milk equals. That said several members have mentioned that they use less than 5% superfat in their soap recipes. I usually wait until thin trace to add honey to my soap. I know from experience that...
There are many EO combinations that will last in soap. The trick is choosing a base note, middle note, and top note. Choose base notes that will anchor your other EOs. For instance the combination of cedar and sweet orange EOs is long lasting...