For what it's worth, you can turn the cam sprockets all you want, just don't lose track of how much you move them from the initial timing marks. I rotated both sprockets to tension the cam lobes against the valve springs to aid in setting the belt to correct time. (It eliminated the need for a helper or breaker bar and bungie cords to hold them from their 12 o'clock off-lobe position as per Barts write-up.) Set the belt to the correct position on both cam sprokets and then rotate the sprockets back to time, tensioning the belt in the process.