Well...
I think I solved the problem.
I'm embarrassed to admit this, but given all the help and suggestions I received from folks on this site, I thought I'd come clean

.
I tried timing it again with the timing light and found the light was only firing intermittently. I changed the lead and it didn't change. I put a new spark plug in and she running golden!
Yes - I did replace the plugs in my original troubleshooting, so perhaps go a bum plug. Because I can't see the timing marks (which I finally found), I don't usually use the timing light to time it. Glad I chose to do it this time.
I normally wouldn't admit such a stupid feat, but I though those who have helped me may enjoy the end of this saga!
Glen