yeah, there is really no way to tell how far along she is. what you can do is monitor her weight, and when she really starts gaining weight is when she will be near dropping (as in the last stages of gestation, the babies do a lot of growing). Also, keep an eye on her and see how lumpy she gets, again, near the end, she will really swell up and you will be able to see the babies above her pelvis. I don't think she will eat the babies though if you don't find them in time. Maybe a male would, but a female who jsut gave birth will not. I watched a program on namiqua chameleons, it was a documentary, where they followed a female around the namid desert, any how, it showed her encounter one of her young after hatching, and she did not eat it. I don't think this was staged, as it showed another baby get eaten by an adult male namiqua. Anyways, I am pretty sure she won't eat them. When my female dropped, she did fine. I got 17 babies out of her, and later, I showed one of the babies to her, and she judt looked at it. She never saw them as food. Same with melleri, one keeper showed her baby melleri to her mother, and there was curiosity, but not as food. either way, just make sure the cage is baby proof, so if she does drop, you won't come home and have baby jacksons all over the room, as it is instinct for them to spread out and get away from each other as to avoid predation. Don't be upset if you lose a few as some babies are born as "distractions". They are born to run, and aren't really ment to survive. I'm not sure how true this theory is, but I have read it from several sources, and I had one baby die within 24 hours of birth. But I don't know. Anyways, good luck.
Anthony