First of all: thank you a lot Gidde for the amazing tutorial. And congrats to the mappers who uploaded their attempts (sometimes even very first mapping attempts). I thought they looked wonderful.
Thanks as well Milesteg for bundling the brushes.

I was trying to recreate the custom brushes in Procreate (iOS app), but there I seem to have hit a snag. I think it's software related and might not be overcome, but I'm asking none the less should someone have had a similar experience. When making a custom brush, black is taken as opaque and white as transparent. When using the brush, the parts that stay 'white' in Gidde's tutorial actually are transparent and so what's underneath shows through that part of the mountain. I presume that the custom brush in GIMP actually takes the mountain as an image and retains the white color like that (I've read somewhere GIMP has 2 types of custom brushes, image or grey-scale). I don't seem to find a way to make a custom brush in Procreate act the same way. If anyone has had better luck, please do share!
(PS: perhaps it's more appropriate to post this question in the Software Discussion forum?)