The CEM Crown Extruder Invention

[JRDM]

It's a nifty idea, but I see too many potential problems. For all the hassle, I'd suggest a second machine for a different nozzle size. If you're doing a huge model, then a large nozzle for infill and structure, and a finer outermost perimeter might be best. But a slicer would need to be made to do that. And there's still oozing and a question of how heavy that makes the carriage. Weight matters a lot. That big potentially heated bock could be a problem, very slow to heat and heating any unused nozzles will mean crusties.