oh that looks nice!!

I would do FMQ in a large stipple like stitch. Always my favorite.

I did mine in an all over meander (larger than a stipple and lines can cross). I was pleased with as was the person who purchased it at a church bazaar.

I did a couple of them with a big meander - no crossing lines - and I am pleased with how they came out

I used a Jelly Roll Rave to practice a variety of different patterns. The lines gave me boundaries to work within. When I was done I cut it into smaller pet quilts. The Jelly Roll was not the prettiest, but cats and dogs do not care.

Since the jelly roll race is all straight lines, it might be good to have a curvy quilting design. If for a boy, there are always meandering stars, for a girl flowers.

I too did a large stipple.

Or if you want to go "modern". Since the seams are horizontal, go vertical straight lines...you coul vary the space between each line, or start vertical and slowly go diagonal til it becomes horizontal...do it on paper first to get some ideas, or go to YouTube...

Sure would take a lot of shells.

I agree with Dunster, an all over swirly or even the meander. Jelly roll fabrics can be busy so often the quilting won't show much anyways. Another option that see coming up a lot is one large continuous spiral starting in the center and working out. DSM quilters are using the walking foot and the foot distance for the spacing. Many report only the first few rounds are problemmatic due to how tight the spiral is in the center but as you progress outward it is very simple. You can also do the spiral FM.

Here are some examples
https://www.quiltingcompany.com/lear...uilting-daily/

http://eyecandyquilts.blogspot.com/2...-quilting.html

This page has many wonderful examples of walking foot quilting. The spiral is about the middle of the page
https://sewfreshquilts.blogspot.com/...-quilting.html