itch.io

There is a good simulator of the Sonic McDonald's games by Difegue, called LCDonald's or Sonic McOrigins Plus.

The graphics have been used for RetroFab versions.
https://difegue.itch.io/sonic-mcorigins-plus

I'm an artist working on a few homebrew things and would like to talk to you about it when you're back from vacation (?)

It's nice to get a Game Boy Studio course (in progress) from Gumpy Function, who has created many high quality games for the platform. I look forward to looking at it more closely.