I personally am not that fond of averages, but they are faster to calculate and easier to read, so major props for doing all this calculations. I may or may not do some myself, but for now I don't have much time on hand.

Anyway, without PF shortening FB strike from 8T to 6T is quite a difference in my opinion which is definitely not meaningless. With PF... tbh considering PF I would use Shingen instead of Herc (and I do plan to do so if I pull Vohu), since in most cases Herc's Axe doesn't matter that much for debuff cap (it's easy for water to get C frame DEF down).
And as numbers are nice and all, and I like to use them myself in most cases, in others it's hard to include everything. I can only recommend trying to use Saraswati in your team in some compositons, it may or may not work. I don't know what Kamihime you have, but if I remember right you have both Cthulhu and Asherah, so I personally would try something along: Shingen/Saraswati/Cthulhu/Blank/Asherah, using BG boost on Cthulhu (and praying for her 15 BG to hit) and combo rate on Blank spot. This thing should be relatively fast (though this works kinda weird with Asherah which specialises in fat FB).