What an awesome project! When I began FMQ I followed Leahday.com. She has many videos that start from the very basics of setting up your machine for FMQ and then goes on through many different designs. One of her early projects was to do a FMQ design for each day of the year. Some much useful information in one place.
When you choose a batting for your quilt, it will tell you how close together the quilting should be. That can vary quite a bit depending on the type and brand. Personally, I prefer Quilters Dream batting, all types, I've never had a problem with them.
I have done a fair amount of applique quilts and prefer to quilt only the background and not through the design. Sometimes I like to add a little detail to the applique piece and this can be used to help anchor the it if need be. It sure sounds like your buttonhole stitch was quite detailed and I would be surprised if you would need more. Just for comparison, I just completed quilting a quilt that is all appliqued butterflies in 10 inch blocks. I did an outline stitch just outside each butterfly and then a pebble stitch all through the background. I used double batting because I wanted the butterflies to stand out.
Can't wait to see your quilt!
Last edited by suern3; 08-11-2020 at 02:02 PM.