Thanks Grumpy. It all makes pretty good sense to me, now that I've re-read it and you've responded to my questions. I agree with most everything you say, especially about people making their boolits too hard.
I found what is probably the same article by Dennis Marshall in the Lyman Cast Bullet Handbook. It's about a 12 or 13 page article which goes into a lot of scientific analysis of lead and lead alloys. Talks about binary & ternary alloys, metallic solutions, etc. More light reading!