Excellent!

Not only is a book I've ordered coming in tomorrow, I've learned another trick in Clip Studio!

The book in question should help me finally understand and recall the names of the muscles used when watching someone draw. It's a little embarrassing to be watching an artist and not have any clear idea what they're saying until it's drawn, so this should be in tomorrow unless the post office has a problem.

In Clip Studio, I've finally learned how to tamper with the light source on its poseable reference dolls by complete mistake. ...kinda shameful, because I'm certain one of my friends told me about this and even walked me through it at least three times...
Let me (attempt to) save anyone else the trouble. The Light Source checkbox is under Tool Property when you've placed any 3D object on the canvas. Click the plus symbol beside it and you'll be shown a sphere where you can tamper with where the light and shadows fall. There's also a place underneath that where it changes the width of the lines around the object.

Note that this only works before you've finalized what you've done with the 3D object.

I don't know if this is exactly true for anyone who uses Manga Studio, but I was told that Clip is just the download version. If the instruction is different for MS, please leave a comment and I'll be sure to edit this post.