Thanks. I was able to get them over. Mostly, anyway. I had three folders of eddresses in T-Bird, call 'em One, Two & Three. One was a full success; Two made it into Live but is gone from T-Bird (OK, since I won't be using T-Bird now). Three disappeared altogether. That's OK, too; it was "Collected" which was just eddresses I saved so that the spam filter would find them, not because there was any likelihood I'd want to use them.
When I'm doing this kind of thing on the computer I call two out of three a good day.