I do a lot of FMQ and a little ruler work. My experience is : if you can draw it, you can quilt it. The best way to get better at freemotion, in my opinion is to doodle. Practice the designs you want to quilt on paper. I recently was asked to do a christmassy design on a quilt. My immediate response was, " I hope you don't want holly leaves, because I can't draw them." Well, guess what, after a few sessions of drawing holly leaves on the back of junk mail and doodling during a lecture, I can draw holly leaves. I've graduated from pencil to ink, and am nearly ready to quilt holly leaves on a customer quilt. It's really about muscle memory, and 'seeing' the design on the quilt, which helps guide you when you're quilting. (I'd also do a little practice sandwich, even if you set up your DSM to fmq for practice, the motions are essentially the same.) Good luck on your quilt, it's darling!