The first time I made custom pillowcases for a guest bedroom, I picked a fun voile fabric but the weight was too light. The type of cotton was clearly different from the body and the cuff. The size was off (they were supposed to be king size), and the colors were not great with the other colors in the room. It wasn't until I upgraded to high end designer fabric that the colors and type of material really went together.
Good Luck with your designs!