Hi Paul, so some further investigation into potential problem geometry, one thing that is not so great is the surfaces are fairly stressed with little ripples and bumps in them, that can tend to happen from trying to force a single surface to be constructed through a lot of changing shapes especially with inflection points in them. So those are areas such as here:



Sometimes those kinds of surface quality problems can be so pronounced that the surfaces zig zag back through themselves in those spots. I don't think you've got it quite to that level here so I think you can get away with these but it's generally not a great thing to have.

- Michael