"Did you schedule the art studies or simply allow them do it as they wanted? I debate a lot about whether its worth setting aside the time for art study."
Art is really, TRULY my weak area, for that reason I basically reserved time for art study, or else we would most likely never do it! We never had a challenge getting math or science finished, only art, LOL! I planned it for 2-3 times a week, 1-1/2 or 2 hours at a time, depending on the year. Never the less, it was one thing that we from time to time simply didn’t do. (Art is so messy, you understand.)
We did the book “Art Fun” the first year, the Feed My Sheep for two years, then Draw Today. We even did a few pottery classes, and that was enjoyable. I own a few art games that they played, not to mention there were a number of books on artists that I had them read over the years. When your kids just “do” art, then it's possible that you don’t really have to have art study. We NEEDED art study, as my kids didn’t ever Get it done otherwise.
We do it bits & pieces with my older. My younger is a budding artist, so no worries there. I find art everywhere. Literally. This weekend we were wandering through a touristy town and found a gallery selling very high quality local Native American art. That was good for fifteen minutes of Art Appreciation.
For all classes on the transcript, I recommend either a whole or half credit, not smaller or larger. Here an easy to remember "formula" for dual enrollment college classes: