is it or will it ever be possible to add a behavior already in Photoshop? If I test something out and then change the structure of my character, behaviors often disappear. I then have to add all the behaviors again to see how my final character works with the changes that I did, and that's a lot of work. If I could add the behaviors in Photoshop already, I think there would be no or less problems, but I couldn't find a place on the internet that says behaviors in Photoshop exist.
The problem with adding more rigging stuff into Photoshop is that the program isn't really meant for it (and remembering the codes/tags to write gets complex, let alone non-customizable for the number of parameters inside them). Ideally we'd do a better job of remembering parts in Photoshop inside CH and syncing better. This has gotten better in recent releases but we still have a ways to go. I tend to leave behaviors until I know I'm done with a particular structure/part - so if I know I'm more or less done with the eyes, and they're in the head and I know it's not going to change much, then I'll add behaviors.