it is still uncommonly to see your construction of this half model ...... but cool idea -> we love half ships, but usual they are cut after building of the full hull, so it is very interesting to see if your way is working.
Do you ask, if you start to fix the framing intop of the keel now? So it is all dry fit without any glue?
Yes - I would do so , because we can see, that some frames, in moment only fixed with your rubber bands, are not parallel or alinged - and not aligned, you will be not able to align or prepare correctly the following one
Step by Step without any hurry