Yes, Pixler, I assumed you know that tool. Based on this thread, this is the tool that gives you the most precise results. I should have explained more.
The “Spline Smooth” is a great tool, and it needs care. The key is certainly to understand what it does, based on ones actions. The Radius parameter is key her, from my point of view. This radius is the processed area for that moment. Teh smaller it is, the more details one can expect. If too large, the results will suffer. Besides that, one needs to understand that it creates or deletes points. This two parts result already in a huge different spline, based on its settings and of course its mix.
As an additional note, I have the impression that the tool works better with less initial points on the spline, and a nice tight mesh to project on.
I have created a little clip, that illustrates this in one minute. I hope after that, you can create what you need with more certainty, or at least decide what works for you and decide then. Either way. I hope the clip illustrates it.
The tool icon is an “iron”, and this will be a constant reminder that this tool is not to underestimate in the changes it does! Its hot ;o)
(Since I record from a 5K screen, the capture itself “eats” a little bit processing, so it looks less fluidly.)
All the best
https://www.amazon.com/clouddrive/share/0Ha5YCgk9MuMfEzpPNH3eQZ3EtPVscm04NdYgOzcSiA?ref_=cd_ph_share_link_copy
[you can download the clip]