Well, 390 is the safest range. With the 4 ACC zeta build I posted a few days back, you get 386ss, which is still manageable for me to get 9bfbs. The timing is tighter for me due to my higher ping.

I've not really tried to see how well 9GDCs bfbs work at 400+ ss, but LS FT/CT rotating doesn't work as well without having to clip GDCs slightly.