Originally Posted by illinois

Ten inches is a lot of open space! I suggest the standard of 4" or the width of your hand. Too, it depends on how this project is going to be used. If it's a wall-hanging that is only for display that's one thing but, if it's going to be on a bed or actively used, that's another. And then how often will it be laundered? A lot of considerations here.
As to tying vs quilting in those open spaces. I'm remembering a piece that I tied with black embroidery floss. It looked like spiders! I took it out and used a brighter color.
Depending on the look you want to create, maybe use crochet thread and bury the ends inside the piece instead of letting the ends show as with more traditional tying.