If I worked somewhere like Criterion this would be my definitive breakdown:
Original theatrical releases seamlessly branched with 70mm editions. 97SE trilogy as a Bonus archival version.
SW in original mono, stereo, 70mm mix (4.2 original or upmixed), and 93 mix
ESB in original Dolby stereo, 70mm mix, 93 mix
ROTJ in original Dolby stereo, 70mm mix, 93 mix
The grain shouldn't be touched, the problem is the color timing. Almost every release has variations, so the best representations would be the original masters and the Technicolor IB prints. (are there any for ESB or ROTJ?)
All around I would just want the most untouched release possible-one that matches the original film as much as possible. The only technical gripe I have are the darned garbage mattes.