I was able to make more progress on refining the second half of the center section, see picture below:
The challenge with this section is building it so it folds properly into the first section for transformation, it sounds easy but of course it was not. Fortunately with a few tricks and determination I was able to get it to work. This is where I am at now:
I’m still short on white pieces thus the mismatch colors. This section will be all white and all new LEGO pieces once I’m done. Here is a picture of middle section as I tested it for transformation:
I would have preferred the top section to sit a little deeper into the first section but this was the best I could do and I think it is very close to the line art I have of the SDF-1. I’m not going to do too much more with the second half of the middle section until I receive more white pieces. This was fun to build (so far) and it turned out better than I expected.