I did something similar to the Bonnie Hunter suggestion... I got a standard sewing measuring tape, and cut about 6 inches off, used double sticky tape and taped two layers of it together. Thankfully, I have a front loading bobbin on one machine and a side loader on the other, so I only remove it if I'm doing free motion. Measured 1/4" from my standard needle position and then used the double stick tape to stick it to my machine. Not only did it help with my scant 1/4" but it also helped with the issue of the fabric shifting at the end of the seams.
Also, it helped me a lot to think of the 1/4" not as the "sewing line," but as the "folding/pressing line." So the seam allowance is for where it's actually pressed, the seam itself would have to be just to the right of the folding/pressing line. I would get so frustrated because I'd measure my seam and it would be 1/4", but for some reason my blocks were wonky... It's because I wasn't getting the idea the the 1/4" is where you want to press. That's probably really basic for an experienced sewist, but it totally was a lightbulb moment for me.
