As Hugh already said: ProRes is no problem today - but AIC is no longer satisfying on the quality side.

With multichannel audio I like to have a separate machine just for audio playback (or even a hard disk audio player - triggered by MMC) and add a channel for SMPTE timecode.

This timecode then acts as the sync source for all Catalyst that may need it. If there happens to be a global delay in timing you can easily adjust with the TC sync timing playback controls (found on layer in- and outpoint controls).

Because of individually running gfx cards´ clocks you might see a few retiming frames during playback - I would say like one in three minutes - but that is usually smoother then ID-syncing or free run...