A little tricky! 😄
As Visuhole makes a perfect Drill, Carve, Emboss..
Scale your object, scale your Stencil
Apply Visuhole for the groove
And Slice! (With Su_Slice by Suforyou)
GIF_visu_slice.gif
Maybe some Guide lines will be necessary...
GIF_visu_slice02.gif
Will be the same for your mountain surface! 😄
bloc.jpg