Well, for what it's worth, I now have a GOUT-synced "hybrid" mono track for Star Wars. Here's how it was assembled:

Reel 1: Spanish 35mm capture from -1 for fanfare, English 35mm capture for everything else

Reel 2: Belbucus audio to cover a little damage at the beginning and end of the reel, English 35mm capture for everything else (end of reel 2 is Tarkin saying "one swift stroke")

Reels 3-5: Belbucus audio

Reel 6: Spanish 35mm capture for the awards ceremony through the end credits, Belbucus audio for everything else.

I tried patching in Spanish 35mm audio in other places without any dialogue, but it just didn't work well. I actually think the result is quite listenable and the transitions are relatively seamless. That said, don't just assume I didn't make some sort of rookie mistake and screw something up before you go do something crazy like deleting your other copies of the mono mix.

The track is available in FLAC, DTS-MA mono and 112k lossy AC3. PM me if you're interested.