Looking at your frame mods, two things come to mind. 1. the rigid BB32R factory frames which were based on the swingarm frame front half typically had a vertical tube around 6 inches forward of the back axle, probably have a factory drawing on my other computer and theres probably a copy on this website - but this tube on each side helps stiffen up the frame
2. there was a forum member looking for some footrest tubes recently and you appear to have some spares
Look forward to seeing progress, what style of build are you working towards?
have attached an image of Bender, my own replica rigid frame as reference which is documented in the the road rocket racing sidecar.
I look forward to following your build!