the 2 product don't match- the 2 by  8 is made better and the wood is thicker and the slot support id better than the 4 by 8.
you replace the 4by 8 with the exact product bad product and because of the 2 different sizes of the products you can not attach them.
the replacement product is in my shed, unopen and will not be used. I really would like it replaced with the wide, thicker wood.