I want to get a new iMac with Flash storage. I work with lots of large photo and video files, and am thinking of using external storage whether USB3 or TB to access these files. I will primarily use the built in Flash storage for the OS and applications, and for any files that get download to the Mac, and as a temp storage for files, etc. 1. Is it a bad idea to only go with 256GB? 2. How much of the 256GB needs to be freed up to keep the Mac running good? Does this work the same way with Flash storage as it does with Hard drives, where you need to keep a certain amount free? 3. Based on my description of how I plan to use the iMac, can anyone give me any opinions of why it might be fine or why I should consider more space? Thank you.