Building a cage, size suggestions?

I have built all the racks I have used for my ball pythons, and have always thought it would be cool to build a custom naturalistic cage (for any herp). I have decided to take the leap to build one for my crested gecko. I only have one as of now but am planning on having a trio of females and one maybe two breeder males. I would like it to be big enough for at least 3 cresties with mostly live plants. I don't want to go with the smallest dimensions needed, at the same time I don't want to build them something too big that will stress them out. What have you guys found to be a good in between. Thanks in advance.

I've never owned cresties so I'm probably not the best to answer this but I would say a 2'Lx1'Dx2'H box would be fine for them.

I would probably go with something around 18"D X 24"H X 24"W. That's about the size that we have our 3 adult females in. There's plenty of room for plants, wood, etc. but it's not overly hard to find them for weighing etc. when you need to. It works well for us. I would only recommend putting one male in with them though. Males will fight.