If it gets to 40 twice year.. it gets to 39 at least twice a year, at 38 twice a year and 41 twice a year and 42 twice a year and 43 twice a year... you see where this is going. Any temp below 78 on the cool end can be detrimental to ball pythons. If you're going to house them in glass enclosures outside the heat will bake them and i'm pretty sure it gets to over 100 in florida too. I'm in Maryland and we've had over 100F days here and i'm well north of florida. The summer may be over now but what about next summer? Flexwatt has a range of temps it will work in, I dont think freezing is near those temps (you'd have to ask someone who works with it more often though). You will definitely be replacing equipment more often because of the temperature changes.
We're advising you against this (some better than others it seems). You still didn't discuss -WHY- you cant house them indoors. Perhaps giving us that reason can help you as well. Giving us all the info will only help.
I feel that outdoor US conditions, even in the far south, are too unstable for BPs. You can't honestly tell me with a straight face that you've never had pests in your home, let alone a screen-enclosed porch-type area. (PS, padios are open spaces, decks are open spaces). This will become an issue for you. What if you get an ant infestation? Ants are nasty creatures and your animals in outdoor enclosures would be literally at their mercy. They'd have no place to escape to. Carpenter bees? (They love wood). If you've got lights at night they attract a whole multitude of other annoying bugs.
And like I said before, even people with tortoises bring them indoors for the cooler months. No one leaves herps outside that can't handle the temperatures. You can't have a perfectly stable enclosure outside where your temps need to be in the 90s and outside is in the 40s. Your ambient temps wont make it past 50, and then you have humidity to contend with.
I feel that doing this would seriously put your animals at risk. What you are basically asking for is RIs for your BPs. Im SURE that isn't what you want. You don't have room for the enclosures? What enclosures do you use? Have you thought of using a small rack? You can even use one of those as a night stand or table. I have a 6 slot rack and it takes up a little more than a 2 x 3 foot area on the floor.