To finish the second sawhorse, we'll use a similar technique to the one we used on the first sawhorse.
Notice the position of the end stringers in the image above. Place a piece of 2x4 on top of both side stringers overlapping the legs at the ends. Use the legs to scribe cut marks on the end stringers.
Cut the two boards to the lines, and attach them to the legs with 2 screws on each attachment point.