PS: At what sample rate and what bit depth? Who will listen? Bats,
humans, god?
48 Khz 32bit float is what you need, perhaps less bit, but do you get
audio jitter or any other issues?
For your 48 KHz x bit don't care too much about the optimized leveling
for the analog and digital side, it's likely more safe to keep the
digital side much below -3 dBFS, than to optimize it to 0 dBFS.