3 weeks should be enough time to let one shine over the other, maybe
in my experience, it's been a crapshoot with seeds anyway. I likely haven't run stable enough genetics, though. I'd pick the cutest and give her a run for her money... then start keeping clones.
In my Kitchen Sink thread, I used a 3-4 week old plant that never had the right environment and hardly any nutes. Then the clones took 2+ weeks to root. So... i'll be sewing a seed to clone shortly after I flip to flower. I'd rather have clones itching for the tent than have my tent sitting empty. I hate that feeling.
I know what you mean... someday, brother, someday. It doesn't take much to make a dry box but, regardless, it's more crap to buy and more work to get set up...
I've had great germ rates, so I can't complain there.