Is it better to wait on the UC App and try to retake the SAT/ACT or is it better to submit your UC App right when it opens with a score you think you can improve on?
It is best to submit your application by Nov 15 only because in the past, the server has crashed with all the procrastinators. I would submit when the application is complete and if you need to wait for your scores then wait as late as possible. There is no right or wrong, especially if you state you are taking the exam at a later date.