I'm currently at about 50 out of 50 successful molts on the new material(s). There have been NO, repeat NO mismolts from my L4-L5-L6 in the new enclosures.
Now, it bears mentioning, that I'm using new materialS...
plural. As Alice noted (with both twigs or mesh), the light is dimmed, and they tend to spend more time in the middle of the enclosure. One of my enclosure experiments is a fully screened cage with double flouro tube lighting. The mantids spend all their time on the top, where heat and light are much stronger. When I see one drop towards the middle, it is always to molt.
My point of materials-plural, is that the other enclosure elements (wired ferns, sunflowers or sponges) have all proven to be molt-wortyh for these instars (we'll see how they do for the final molt). I'm happy to say, I have the numbers to support these experiments, and enough lag time between the multi-aged nymphs to adjust as needed.
All that said, I think Precarious is correct (albeit, not in the direction I want to go), when he says to eliminate side molting options. If I were to design a single-mantid molting chamber, it'd probably be a small glass enclosure with the nylon mesh top, and a single, angled branch leading to the top (and for side grabbing during the flip. But, as mentioned, I'm trying to engineer an environment where the colony won't need that level of attention, and I can occasionally leave the office for fun and adventure!
I'll keep posting results. If y'all have other suggestions, please chime in. I'm confident we can take these beauties off the list of "Experts Only". They are, as I've mentioned several time, THE most rewarding species I've yet encountered.