As a constructive point, i'll mention something that I got reminded of recently while working with a similar style - At least in the case of the Blaeu maps, the shading lines tend to follow the shape of the hill contours. I tend to do mine horizontal too, so you're not alone I think it would be easier (digitally) with an app that will let you rotate the canvas (photoshop cs4 won't work for me, argh), I have yet to try my hand at doing this on paper.

Hrm. maybe that's a good excuse for me to clear off the table and break out my pens!

Still nice work.