Hi, I have two red foot tortoises that I got from a pet store recently I've had one for about a month and the second for a couple of days. They both seem to be doing well and getting along together in there enclosure but I want to build a bigger one now that there are two of them. What should I use for wood? How big should I make it for the both of them? What substraight should I use? And should I turn it into a bioactive environments? My first one is about 4 inches big and the second one is about 6 inches big.