Jonathan, It appears that the 2R in the post title is working as I had hoped, that is, keeping the thread 2R oriented, but NOT restricting participants regardless of their modeling preference. That is evidenced by posts from Bob Bartizek, who models the PRR in 3R. Bob has likely forgotten more about the PRR than I know! He is very knowledgeable.
As for photos, I've long been an advocate of prototype photos (especially builders photos) to aid in getting things correct. They may not give you correct dimensions, but I can certainly use them to tell whether or not a model "looks" like the real thing!
Regards,
Simon