Yes, those scoring marks, so characteristic of how timbers got squared up in the North American places. I like this look very much, thanks for explaining it some.
I am finding that I like squaring-up at a height around my knees maybe even just above that. Like that I am able to relax quite fully, upper and lower body parts, and work in a natural position maintaining, more or less the same posture for all the operations, notching, wasting and surfacing, like I said it before, a unity, none of this being my design but what I have observed.
Right now I've got things set up for squaring up out back on the site where my sheepshead that got crushed under a falling tree's getting rebuilt. The ground is sloping there so it has given me the chance to try out all the possible heights. I must say lower is better than to high.