I haven't touched QPI PLL, i've still to find out what CPU / QPU PLL does.

All i did was set 1.44v QPI, remove other bottlenecks (low cpu multi, memory, 17x uncore 18x QPI). I went straight from stock to 1.44v aswell, so i'm not sure how much i actually need, it could be less.

Maybe chips will vary in max stable bclk as much as they do in max stable cpu clock?

P.s i've not seen any evidence that vcore affects QPI. I had 1.275v set when i was 1.44v QPI + 213mhz stable.