But...reading back your posts I think that I can add I function to save a customized pen (or brush) to be reusable. So you could create some missing pen with the actual UI, save it and reuse it every time you need.
Of course full customization cover more or, better, any scenario but the problem, now, is the massive use of 'Graphics' and 'GraphicsPath' objects. I have to remove it in the code using more powerfull object at least for the internal cache (for final drawing, at now, is not possibile...in future I have planned to migrate all to skia or siminal graphics engine).