Al - this method works for me - not for everyone - but - while building the OLDS motors, I got in the habit of permanently marking the dampeners. Saw cut a tiny groove and blackened it. I've added some marks to the bird now too.Measured the OD - multiplied by pi - and calc'd the circumferential distance required to place a mark at the "full advance" timing point. Now - I always "power time" the engine by reving it to high enough rev's to reach full advance and then lock the timing at the top. If you have your set-up right - it will drop right back to the proper initial at idle.