All things considered, it seems as if the best results might be obtained with a combination of the DefCol, "Faces" and SC sets.
Given Citizen's comments, it would be interesting to see a comparison between pre- and post-THX frames after you've cleaned them up and colour-matched them.
The other point that seems pertinent is to establish whether the SC is visibly better than the US '89/'90/'92 set which is apparently from the same transfer.