What Thieum said. Additionally to answer the other question, yes, the profile would not be two concentric circles. The inner circle would be slightly elliptic and slightly towards the face. No need to overthink it though. It is a simplification after all :)

Hey, Peter! IMO, it does and it doesn't matter. "What brush do you use?" is almost a meme at this point, but brushes do make a difference- and I think it mainly comes down to experimentation and feeling. Like some artists prefer charcoal pencils, others prefer charcoal sticks, neither is better but one may just feel better for you and you'll get more out of it. Generally speaking, you won't develop bad habits from using the wrong brush. Bad habits just come from process, cutting corners, using shortcuts instead of learning fundamentals, etc. I think focusing on specifics like what brush, what size/opacity, etc. isn't super important. What's more helpful is to set a goal and experiment with brushes to get there. Like if you want to get better at more painterly styles, do some painting studies and try out some textural brushes to see what you can do. If you want to get better at hyper rendered splash art style, you can try a study with just hard/soft round brushes and see if you can nail that hyper-render feeling. So my general advice would be: - Set some goals on what kind of markmaking you're trying to achieve - Get some free/paid brushes from artists that will help you get there, or make your own - Try out your new brushes and organize them. Keep the ones you like, delete the ones you don't like. Having a massive, disorganized brush library is a nightmare. - Learn your software's brush engine. Being able to make your own brushes helps a lot, and it will help you understand why some brushes work for you and others don't. And you can even edit brushes that "almost" work for you to make them perfect.