Wow. This is a thorough, hour-long video on making your own slide hammer seeder for TINY seeds. This guy is a big fan of purslane. Alyssum and purslane are a couple examples of tiny seeds that he uses this seeder for.
Even in a polyculture system, I find there are advantages to seeding some things in rows, with or without a tool like this, so that you know it's something intentionally planted and not part of the chop-and-drop milieu.