Insets Along Curved/Tapered Surface

 From:  Skwerm
First, thanks for all the help!

I'd accomplished something very similar to your suggestion shortly after posting the question. We're getting close!

However, as I'd stated in the original post, the grooves are not sharp extrusions inward. Instead they are kind of half "hot-dog" shapes removed from the base mesh. I'd said something about being able to create a cylinder with hemispherical end caps and removing them with a boolean operation.

So the current state of affairs is attached to this post. I drew a vertical line, projected it onto the curved surface, and then used the resulting curve as a sweep curve. I then capped those ends with spheres and bool-added them together and removed them from the base.

So far so good.

However, I can't add fillets to the edges of the removed areas. The boolean removals worked fine (I think) but I get no result when I select the resulting edges and try to apply a fillet of any radius.

Again, many many thanks for the help. If I can get filleted edges I'll have the solution to the problem.