Michael, thank you very much for your input, yes this is exactly what I was looking for!

For future reference, I'd like to understand the logic of first trimming the top surface of the ring please? Is it to just restrict the lattice from stretching?

Why is this not needed when you use curves as I did before?

Apologies for the questions but I need to wrap my head around the reasons so I know what to do in a similar situation down the line.

Many thanks indeed.
Gunter