There is a trick to this u speak of force growing.
Instead of light on longer, after 12hour light cycle, keep the temp the same for 5 hours.
Dont over myst ! Just take a q-tip and dip it in disteld water. The mantis will drink what it wants. "But u have to keep trying"
Faten your feeders ! I know it is expensive, but its worth it ! Get Powder Baby formula "Symalak" On the back lists every thing you need. You can skip the 100 ingredient mix for now on !
Feed ur flies/crickets a banana chunk.. then powder them and feed to ur mantis.
Feeding cycle. Well, when they hatch from the ooth.. i feed them fruit flies, all you can eat. weening them off the 5 fruit flies to 1 house fly is easy, just rip off the wings and the front legs. In most cases that fly will die b4 getten eaten, so repeat till it eats 1. "If the mantis is a lil scared runner, wait another few days, or try a house fly that just hatched.
After they are on house flies. Just leave 1 with damaged wings for about 6 days. After 6 days u dont wanna risk leaving the fly in wile its close to molting. Then you will have to feed and watch. Then go the same to ween to blue bottle flies. When they get to blue bottle flies, start tring to feed them a lil banana or grape on a tooth pick every day b4 you turn on the light n heat. You want to feed them at the start of the day light so they can take that heat and digest quicker, just like a lizard with a heating rock. Then before you turn out the light. Try the q-tip diped in disteled water or the grape chunk on a tooth. so the mantis can use that to flush the food out for the next cycle.
Add more insects to the diet. Theres tons of healthy insects to feed after they are L4/L5. "NEVER FEED OUTSIDE CAPTURED INSECTS !"
Before Molting. They will stop eating 1 or 2 days b4 molting. In replace of food for them days use q-tip disteld water or grape on a toothpick.
Feed them other mantids... usualy the mis-molts. Also, if ur female eats the male during mate, she has a great chance for a over sized ooth layings.
My Pseudocreobotra wahlbergii layed an ooth 4 inches long and was really thick... 3x as long as 1 i ever bought off the forums.
Anyway, this is all time consuming, and u have to remember, like a cars motor with turbos or a computers CPU with over clocking, it will be short lived !