Terry, your indoor redfoot enclosure is in a humid room too. Correct?I'm going to go out on a limb here and talk practical! I have raised hatchlings to be 6-8" -- take a wild guess how long that took? 6-8 YEARS!!! Unless you feed them like a horse.. you want to grow them "slow and steady". I wonder how many here that are showing these HUGE enclosures know how long it takes for a redfoot to get to be 10-12" SCL ??? @mamameg do you think that your life or life-style will change in the next 10-12 YEARS?
I HAVE FOUND.. FWIW - a rectangular enclosure is better than a square because they don't go from their food dish [ on one end ] to their hide area [ on the opposite end ] in a zig-zag fashion... mine have always gone in a straight line. SO - right now 15-18" wide would be plenty wide enough x 4' long will be good for the next 3-4 years.
Over the past 10-12 years of keeping and breeding.. I've changed and upgraded at least 5 times for any hatchlings from 2006. A "lifetime" enclosure now would probably over-whelm your yearling.. I'm sure!
I build for 'purpose' only : For my young/mature adults -- 32" 'wide' x 12' long - cypress mulch substrate.. a water dish and a piece of slate to feed on. One end is their sleeping area ( 4' ) the other end has a single UVB bulb in a clamp light fixture over the slate.
If I were you I would look for [ or build a 'tortoise table' in the space you have ] a 55 gallon aquarium ( foot-print.. 12" x 48" ) or maybe a lower profile "breeder' style like a 40 ( foot print.. 18" by 36" or a 75 of 18" by 48" } - the 75 would probably by ideal.. even tho' quite big for a yearling . Hope this helped ?