You could also use whatever shape as a starting point but then you need to come up with your own solution to filter anchor points. The way I set it up, anchor points are extracted from edges which lay on the hull.
The anchor points you tried don’t do anything since they’re not connected to the initial mesh in any way. My next attempt would be to use the result as an input for a new relaxation. Maybe Triremesh first so the new input has more even edge lengths…