ummm...I dunno....I have some 6-8 inch smaller rulers that I love to use on my longarm (well not exactly love, I would rather free motion than do ruler work) I had also bought longer rulers thinking that they would work better...about 18 inches...well, I found they actually were harder to use as you need to position the rulers fairly close to the foot and spaces you are actually stitching. I would think, the longer rulers might even be harder to work with on a DSM....I think for marking they may work well...but for actually stitching and doing ruler work...I think the smaller ones are a lot easier to use....Just my opinion.