Today I took the plunge and planted my rudbeckia and butternut squash seedlings. The squashlings are 2" to 3" tall and pretty robust. My baby rudbeckia are a little shorter and much more delicate-looking. They also didn't get quite as high a real-dirt-to-clay ratio as the squash, as they're in a spot where I haven't planted before, so this is my first season improving the soil.
If my gayfeather ever germinates (it's hard to be patient when the other seeds have sprouted and are now in the ground), I'll put them in the same spot as the rudbeckia, since there's plenty of room there. I do hope that happens; it would make for a very cheery color combination.