I used T track screwed down to the main waste board, then put strips of 3/4” mdf in between that I fastened with machine screws into inserts that I installed into the main waste board. In theory if I damage one of the single filler strips I could replace just that one by simple remove/replace (I actually cut some extras when I made mine). I’ve yet to actually have to replace one, but I can pretty easily. I did a really long write up a couple years ago (and that write up got derailed several times). You can see it here: