excess grounds do no harm and might mean a problem that won't happen
where does the ground terminal of your battery attach? the battery connected directly to the engine is best for the starter circuit, like to the bell housing or a starter bolt - if your battery grounds to the frame, then put the 2nd strap from the frame to a starter or bellhousing bolt, good idea to have a 3rd ground from the frame to the cab to insure lights and accessories get proper grounds
Bill
