As an update, I did a test planting of this huge marigold in cels under lights, 3 seeds per cel. I got about 33% germination. Not great, and I don't know what the seedlings will produce yet. But I have a good pint of seeds.
If anyone wants to try any, just let me know in Tree mail. I'll be glad to send a couple spoonfuls in a plastic bag in a SASE and wish you good luck. The ones that germinate seem pretty healthy so far.