I think you’ll find that most editors turn that warning off. I edit a TV show and do commercials, weddings…you name it, using prores and have no problems what-so-ever with the final output using multiple layers on a similar Mac Pro. Even when I went to school to become certified in FCP, our instructor had us turn that off right away saying that until you get the RAID and everything, you would always get that message. Just FCP being safe and warning you. Just my 2 cents 🙂