How do I force this bitter to be in chain after specific plugin rather than before?
Indeed, it receives 64-bit data, just verified.
How do I check that Dirac (in my case) outputs 64-bit?
I don't know for sure whether or not Dirac can in any version maintain 64-bits. But, why is that important, given the only algorithmically estimated adjustments to signal it does via EQ, which are based on time-windowed, acoustic readings averaged from multiple, inexact mic points including random ambient noise in the room?
There is a key difference between accuracy and precision. A 64-bit result might be more precise than a 32-bit or 24-bit one, but it might be no more accurate within the tolerances of the measurement and processing algorithms. You have no doubt heard the phrase "false precision". It strikes me that Dirac would be guilty of that at 64-bits.
Don't get me wrong. I love Dirac, and I would not be without it. But, I frankly see no benefit if it does 64-bits.