That washer/flange could make for some assembly issues since they used the aluminum arms for their prototypes and on every photo that I could find that shows the bushing no inner washer is present!

There is no way that my LCA and bushing could line up w/o much more grinding of the alignment holes if I used those washers with my LCAs

It looks like you are coming along. Do you plan on full assembly without painting the frame then disassembly, paint, reassemble?