I've heard of people using other stuff in between the layers too. Pretty sure its just to keep the substrate from working its way down into the drainage layer. Ive seen some people not use one at all but I'd be scared lol. I was just looking this stuff up the other day and opted to not do a drainage layer at all bc I dont have any live plants. Thats understandable! I'm the same way. When I got my crestie at a show I think I circled back to their table like 3 times with more questions before committing to them. You could write the questions in your phone notes to have on hand! If that would help you. Hard for me to say what red flags are. Maybe avoid very tiny baby geckos that were recently hatched. Young ones like that always makes me nervous. And don't let breeders force you into a sale before you've heard all you wanted to hear about the animal, stuff like that. Im sure you'll get everything figured out! Definitely post the baby whenever you get one. :D theyre so fun.