I’m in the process of making the exact same diorama. You have a difficult task ahead of you. Are you just making the light area around the docking bay maw, or the actual bay interior?
Jason Eaton has made a marvellous model of the large squarish gantry hanging to the left...you should check his page for reference. In the middle of the bay, ILM made a miniature of their Dykstraflex camera, which is hanging upside down. That was removed for the Special Edition (pointless change).
The area around the bay entrance on left and right is simply repeated panels of the standard live action wall “Death Star Air Supply System”, but scaled down.
There’s a massive problem with the left side of the bay (as you’re looking out into space), as (very visible at the rear of the live action set) are two cylindrical piston-like mechanisms (which I think are painted flats). This mechanism is exactly at the rear edge of the bay, and is not visible on the ILM miniature when the ILM Falcon is entering the miniature. My in-universe continuity rationale fix for that is that the panel section of the wall either raises or lowers after the Falcon is at rest to reveal that mechanism.
The exterior matte painting of the space troopers with the turbolasers changed the docking bay ever so slightly for the Special Edition.
ALL versions of the docking bay (original and SE) in the film don’t make sense. Peter Ellenshaw made an error painting the bay matte painting in the original film. There is a forced perspective effect created by using ingenious wallhangings, and painted chevrons on the floor of the bay. This effect is only really visible from one spot within the set (spot just below the front right mandible of the Falcon… Ironically, an angle that doesn’t seem to be used within the film.) The closest shot in the film giving this visual illusion effect is the standard “continuity publicity photograph“ of all of the storm troopers standing in rows when Darth Vader enters. ( you could see that the painted flat off the wall on the left hand side of the bay, and very thinly painted Chevron lines behind the Falcon, from that angle extend out in the proper perspective to the regular chevrons painted alongside the lift area by the Falcon). The down angles on the Falcon are painted incorrectly: the entrance maw isn’t extended out to the left to correct the force perspective, neither is the length of the bay similarly altered in order to correctly match the forced perspective trick. Stinson Lenz (who I believe is on here… Hi, Stinson!) and I were discussing this some weeks ago, and Stinson made a subsequent terrific CG representation of what the corrected Death Star Bay would look like.
https://deeplyobsessed.blogspot.com/2018/02/actual-depth-of-docking-bay-327.html
Compounding this fact, are that the CG artists who did the special edition shot completely screwed up the bay. Not only did the dimensions of the lit maw change from shot to shot, but they added in the Death Star 2 docking bay structures from ROTJ, which are totally wrong; and they also made a total balls-up of the left side of the frame (screwed up the wall with a ridiculous digital set "enhancement", and buggered up the catwalk gantry so that it now makes no continuity sense.)