Another timing question

[Peter J]

I have an A dist. on my B block. With an A dist, should I time it at TDC on #1 and disregard the timing pin or should I use it just like timing an A engine as I understand it would be 19 degrees off. When I get my B dist. with auto advance, should I then go to the timing pin on the cam gear and not worry about the piston position and do I center the rotor in #1?
I've looked at the various web sites and they're a bit confusing.
Thanks for your thoughts and suggestions,
Pete