I've never tried to propagate that particular species, so I don't know such things as how long it usually takes to root. Hopefully someone with knowledge specific to that plant sees your post. However, I think most cuttings are killed by one of four things:

1. Medium is too wet and your cuttings rot. I think this is by far the most common problem when using the method you describe.

2. Air humidity is too low and your cuttings wilt.

3. You didn't provide the right conditions for your cutting to root and a cutting can only live so long without roots.

4. The species either can't propagate from cuttings or is so difficult to propagate from cuttings that the method used is extremely unlikely to yield results.

As I said, I don't have the information to address 3 or 4, and they are the least likely culprits anyway. Although I said 1 is the most common problem, it doesn't sound like it is the cause in your case. However, you should take a close look at the stems. If they appear to be black or brown at the base where they meet the medium, and especially if the black or brown is creeping upwards over time, they are rotting.

My best guess though, based on what you said, is that we're dealing with 2 here. It sounds like you might have overcompensated for the mold and reduced the humidity too much. This too much/too little battle about humidity is something I struggle with too. One thing I did recently is that I bought a very inexpensive humidity monitor (about $7). It won't necessarily stop me from screwing it up, but it gives me some peace of mind that indeed the humidity is high enough.

I'd say that if the medium is not wet but only damp and you see no blackening or browning of the stems, then you should reestablish your original humidity level.

Wow, cptk1, thank you so much for taking the time to write out such a thorough reply! You could be right about the humidity. I have since left the lid on and not messed with it, except to rub off some mold once in awhile.

Condensation doesn't appear to be on the cuttings themselves, but it definitely is all over the inside of the tub. Hopefully that's ok.

Is there a fear that roots could actually emerge (undetected), but that the plant then suffers because there's no real soil? Or will it do ok in the moss/vermiculite mixture?

Thanks again, I really appreciate it.

Potting up too soon is probably the biggest cause of failure after you've had success with the hard part. Obviously the cuttings can't live forever in the propagation media, but they can live there longer than you think. Putting a cutting into fertilized (assuming you're using a potting mix) and less well-draining soil too early can definitely kill the young plant. Wait until you get some top growth and some reasonably decent roots before you pot up. Don't use a pot that is too big (too much water retention) and maybe even consider cutting the potting mix with equal parts sand or perlite (most potting soil already has perlite, but for a cutting you might want a lot more for its first pot). (1/2 potting soil and 1/2 sand or use perlite rather than sand.)

I really would recommend you invest the $7-10 in a humidity gauge. I know a lot of people would say it's unnecessary, but I really like it because just for me it's too hard to judge humidity without it. For example right now I have no condensation on the inside of my tub. In the past I would have sprayed water. However, my gauge tells me I actually have 88% humidity in there, which is more than enough (probably too much).

Thank you. What humidity levels do we want to maintain?

That humidity tester sounds good, cptk1.

smeep, another thing that is useful to do with rooted cuttings is to give them some time to 'harden off' before potting them. A a week or two off the heat bed before potting allows the cuttings to adjust slowly to their new enviroment.