FYI, someone did sync the lossless audio from all of the GOUT-synced projects to match Grindhouse. Should come up if you search “grindhouse” on myspleen. I muxed the 5.1 into this and it worked just fine.
Wait, are you saying they GOUT synced the Grindhouse video or they Gringhouse synced the GOUT-synced audio?