Could do.... I'd use cedar deck boards (5/4 x 4" [1 x 3-1/2" actual]) the next time around though and plane them down to size (3/4 x 3"). My neighbor says he won't let me abuse his equipment with that rough-sawn oak crate wood anymore!![]()
Cedar isn't as dense or strong as oak, but it would be supported every 43 inches, so it would do fine as troop seat slat material. Plus it would last a good long time in the outdoors, especially painted. I'm going to be making up a set pretty soon to see how they work. I shall report back and include what my neighbor would charge for the work.
One note on those M35 metal brackets though... Perhaps 503m715 will chime in, but I believe he said the seat supports--the part that goes from the edge of the seat portion diagonally down to the floor when the seat is down (the long parts of the brackets in the upper right of your picture) needs to be either cut or lengthened to fit the M715.