I used Warm and Natural batting and quilted it to two layers (top and bottom) of muslin. I also made a muslin cover for my board. Not difficult to do. I used a drawstring in the casing around the cover, but added some elastic in the mid-section to cut down on the amount of drawstring (which also was made from muslin, double folded and stitched.)
I have a tendency to scorch the muslin cover when I steam quilt pieces, especially things like triangle half squares. I have solved that by using an old pillow case, laid across the board, and do my pressing on that.
I can wash all of it or just the cover as needed and slip it back on the board. Your custom cover will last a long time.
June