Hi and thank you for this thread. Firs post at The RPF!
I'm currently working on building the SD II Avenger and I have multiple questions about proportions and some parts (mainly the bottom part of the ship). And I'm always surprised about how much variations we can find between all the kits (I hope the future Bandai one will be accurate...)
Luckily, I have been able to take a bunch of photos of the Avenger at Star Wars identities exhibition in Paris, enough to produce a scan data of a big part of the model and I'm using it build my own model (I'll go 3D printing).
Because it's based on the original built from the movie, I hope it's the most accurate source. I may do a quick fly to UK soon to take extra photos and hopefully, being able to produce a better 3D scan.
Then on my scan and from the photos, the tower bridge (part below the deflector spheres) has an angle (orange line). But from my finding, on most kits and "blueprint" that can find on internet, this part is vertically aligned with the center line (blue) and not without a small angle. Because the scan was done in very poor lighting condition, I can't guarantee that it's perfect.. but I think I can trust it that some kits...
I'll open my own thread about the work in progress very soon.