Ok, found a second later the post on building a sawboard.
Now the question. If you bought a good guide clamp (or me, a cheap guide clamp from harbor freight for 20 bucks)...
Couldn't I create a width board. Cut a board the size from the blade to the edge by putting a board up against something thicker, like a 2x4... Then cut down that board effectively making it the width of extra... Then keep that with the clamp. Then you measure the board, slide the clamp next to it... then clamp it down.
Or should I just make a sawboard?