Well I was under the impression that the '93 LD's got THX remastering, but somehow, the '95 set turned out to be better (with no split lightsabers and so on), even though it was supposedly the same transfer. I don't know. The thing is, the fact that they put out high quality copies of the OOT in both widescreen and fullscreen in the nineties (remastered in EXACTLY the same way between the editions) seems to prove that they restored prints BEFORE they made lower quality widescreen and fullscreen masters.
Either way, they've GOT to have a very high quality master from which they made the '95 fullscreen VHS release, whether it was digital, an actual restored film print, or what. To say that the "exhaustive search" has only turned up low quality widescreen master tapes from '93, and not the MUCH HIGHER QUALITY source that HAS to have been used for the fullscreen release is just stupid.
I don't know the whole history, so I'd love if someone more knowledgeable clarified.