Hi Sherlstar -- do yo like the way Jenny quilted the one on display in the MSQC video? To my eye, it looks like it's an unmarked free motion quilting-- loose swirls and paisley with a bit of floral thrown in. I think it's a nice approach for that quilt design -- the piecing is very angular, so to have the curving and swirling design in the quilting softens the overall look of the quilt.
I personally don't mark or use stencils -- I find it easier to just "doodle" with my stitching all over the quilt top./ I try to keep my spacing and stitch density even by visualizing an object-- so some quilts I strive for a about a quarter (as in $.25) between the stitching lines. Others are looser, and I visualize a toddler puzzle piece.
I'll also go against the majority and say that I don't stitch in the ditch before FMQ. I start off center and work one quadrant at a time. On the rare occasion when I want the top stabilized a little extra before starting the FMQing I will use a water soluble thread to stitch a grid on some of the more major lines of the piecing. Then I feel free to run my FMQ thread right over that, as it will wash away after it's served the purpose of keeping everything smooth and stable during FMQ.
IF you are a novice FMQer, I'd probably suggest doing a loose meander in a medium thread that will blend well. If you're pretty confident and experienced, I think it would be a lot of fun to pick two contrasting styles of quilting for the stars vs. the background to really play up the pieced design -- something like a swirling spiral for the background areas, and more of a feathered plume within the stars. With that approach, I would match thread to fabrics to leave the focus on the texture and not so much on the actual stitches. If you wanted to get really adventuresome, you could create a little contrast between the medium and the dark portions of the stars. Have you ever taken a look at Angela Waters' blog? She has some very inspiring FMQ ideas (though keep in mind that she uses a long arm and is a pro). I find her approach to be really fun and visually interesting, and I sometimes adapt and simplify some of the designs she features.
Best wishes with your project. I'm sure it will be wonderful. Do share photos when you're done!