Re: Building new cages...
That is a pretty big cage for a ball python.....For an adult ball python, I would go with a 36" x 17" base with a height between 6" and 12". Remember the more 'air space' you have in an enclosure the harder it is to maintain proper temperatures. Also, Ball pythons generally do not like open areas and prefer more 'confined' enclosures.
That enclosure sounds fine for an adult female RTB...how wide do you plan on making it? I would go with a 6 ft x 2.5 ft x 20" for an adult female redtail.
You also have to consider how old your snakes are and their size. Both enclosures would not work well if the animals are still small. Both snakes can become very stressed by large enclosures when they are young, so just keep that in mind.
Re: Building new cages...
I wonder if I could keep them in sterilites inside the cages I built them.Then when they get bigger I'll just remove the tubs.