Thank you all for the suggestions. I had some strips cut for double sashing that I hadn't yet sewn together and used those as a quick test (part of the current projejct so not four wide like suggested). I double checked the cut measurement and they were right on. However, after sewing and pressing (seams open), I lost about 1/16 inch. So i need to adjust my 1/4" marks and try again. At least I know where to look.
I'm almost done with this project (place mats and table runner), so before my next project (full size quilt), I will do more extensive testing and practice.
(Salsa Table set design below)