Choosing the amount of circularizing...

[micheus]

I see that my circularize does already have numerical input.
So if you use "D" command ... maybe it does not take too long ?
Or is it still too hard ?

By planning the model, it would be possible to use less segments, so you would have less edge loops to apply "D" and after that you could use Flow Connect to create the intermediate segments and make your object smooth like shown here.