Sorry Chris I didn't mean to imply reradiusing the rear arch solves all the issues but I do think it improves the look. The arches most closely resemble the Rothmans car.
Ideally both arches should be completely reworked. First for an early car below the beltline and again for a more standard later car above the beltline. However I am not sure I have the skills to pull off all the modification that would be required. For now I think I will press on with all the chassis mods and see how that work turns out.