Select by height would be a very useful tool as would select ridges.
The surface layer and distribution layer have select by height.
Select by ridges/valleys would be good I agree.
Yeah, that was stupid as I only really want select by ridge!
Ok not an ideal solution but play with the numbers and this may get some results.
You can use intersect underlying with a very much larger compute terrain patch size.
You can at least get the idea and experiment towards your own needs.
Hope it helps :)
Cheers and thanks. I will experiment.