The grid matting I have is actually in three pieces, cut from shelf lining rolls. I did lessen the presser foot tension, but may see if I can get by with loosening it some ore. My other plan is to just tack the matting down, kind of like hand tying a quilt, but not so deliberately obvious.
I would be happy to buy him a better one, or make him one---a cute quilt idea? but his mom gave it to him, so I have to mind my manners, lol.