A mate used to do this when tuning VW Beetles. Mark the timing marker with some whiteout out of a pen.Remove dizzy cap, then turn on the ignition. Turn the main pulley until you see a spark from the points. That is the point that the ignition is set to. Move the dizzy body until the points spark at about 10 degrees, then tighten the bolt. The only problem with this method is that you have to remember to turn off the ignition each time or you can burn out the coil if it comes to rest with the points open. You can tell the direction the rotor turns but the position of the No 3 spark plug lead, due to the 1-3-4-2 firing order. Turn the distributor away from the no3 lead to advance the timing.