Do you need to create a new FW page with 72 or 96 PPI based on whether you are working with a Mac or PC, or does it not matter? If it does matter, what happens if you are working between a Mac and a PC? Will your design and layout be affected if you have to change the PPI? OR am I not understanding this concept?
Thanks in advance.
You can make the resolution anything you like for either operating system. It doesn't affect the file size. It will affect the pixel dimensions, however. You'll see that if you change the resolution from 72ppi to 180ppi via Modify > Canvas > Image Size without specifically maintaining the original dimensions.