Because of the open areas you need to have an additional layer of fabric that goes "underneath" the linen. This keeps the batting from poofing thru the open holes. I call this an underlayment.
Can you see the poofy areas of fabric underneath the bridgework? This is personal preference only...I don't particularly care for the poofy areas and chose to go in and scribble in the holes. Yep....every hole! I am careful about selecting an underlayment that complements and blends with the bridgework. This allows me to travel from hole to hole along the embroidered edge and keep it continuous line. This is a "before" shot...
Thank you Debbie J. for such a good question... Hope this helps!
PS: These samples will be at the Houston exhibit for teaching purposes. :)