I'm assuming when you say dry you don't mean where it turns to dust when crumbling. At 40 to 50% RH your plants should be ready for the jar in less than 8 to 11 days. I don't think I've ever gone past 6 days.

If you put them in the jar too early they will moisten between openings. It's really no big deal. I've done it a couple times because I had to (had to go out of town for 3 days). I had someone open the jars each day for 15 minutes. When I returned, any buds still not dry enough can be dumped out and allowed to air a little while then back in jar.

Even moist I've never had a mold problem. But leave those moist nuggets a couple days without fresh air and there's the mold.