Caught up to the manga, my general review:
It's pretty good. I feel like the kid's artistic obsession being pidgeonholed to just painting nudes is hurting things a bit, also not quite certain I understand why he's obsessed with feminine beauty in particular, when he doesn't seem to have any arousal towards it at all.
I do think all the characters are fun, but I do wish the Witch in question, his particular object of obsession, featured more strongly, and their relationship was more fleshed out and better ingrained into the story. I would also prefer any romantic developments to be towards her, but then again I'm a 30 years old man, so it's probably more appropriate for the kid to date his classmate instead of who I'd prefer...