Rotor Position Question

[pjdeb]

I recently read about this method of checking timing:

Remove the #1 plug, ground it against the block, and attached a wire to the plug from the #1 post on the distributor body.

Remove the other 3 spark plugs so the crank will be easier to turn. Remove the timing pin from the front cover and insert it back in the hole using the round end. Push the spark lever all the way up to the fully retarded position. Put the trans in neutral. Turn on the ignition. Take a hand crank and begin turning the engine over to allow the #1 piston to rise on the compression stroke. When nearing the top of the stroke, apply pressure with your fingers on the timing pin so you can feel it when the pin moves into the little dimple on the timing gear. In other words, you will be doing as one does when setting the timing.

The very instant you feel the timing pin slide into the dimple, you should see a spark at the spark plug!

Another reader posted a comment:

This will show you exactly when the spark occurs. The points gap could be measured and adjusted as necessary. The thing that matters most to me is where the rotor tip points when the timing pin drops into place. If the rotor tip doesn't point exactly in the correct position , the timing will be off no matter where the points gap is set.

My question is: what is that "exact correct position?" Is it when the leading edge of the rotor tab is opposite the number 1 tit or is it when the center of the tab (hence the .025 gap point) is opposite the tit?

Thanks in advance.