Thank you for the kind words! For each one I started off pinpointing the toughest areas/curves to create, and then worked off that. There's a lot of thought behind which layers to place first so that subsequent layers can mask over spills or imperfections, but beyond that the rest is pure trail and error.
I give it some love whenever I have some spare time!
Mostly built it so I could generate playlists purely with songs that I enjoy, and be able to easily access that from anywhere and on any computer. I figure you're coming from a similar angle? :)
Don't read too far into this comment though, this was purely something fun I wanted to attempt.