Did you try it out on a scrap sandwich (with batting) or just on fabric?
As long it will go through your machine easily, you regulate the speed it needs to travel, and the back looks good, then there should be no reason you can't do it.
I've used decorative stitches on QAYG blocks. But then all I was dealing with was an 8" square sandwich. Was very easy to control. That's not a 65"x65" quilt.