I recommend getting the smaller WTF from petco and putting it in your current tank as a quarantine and put your current frog in the new tank. Quarantine should last at least a month. When I got Lrrr he was easily half the size of Glurmo but with regular dusting and proper care he was almost the same size as Glurmo after a month! There are still some frog from the same batch at the petco I got Lrrr from and they've hardly grown at all. Lrrr has almost outgrown Glurmo.

For your new viv I highly recommend live plants. My frogs LOVE the snake plant in theirs. It's sturdy enough for them to sit right on it. And I always recommend pothos because it grows so easily and can take a beating (which it's sure to get from WTFs). You should visit the Viviarium forum here. Check out what other people are doing to get some good ideas for yours.