Best Dwarf Boa imperator locality

Well - there are some localities of "dwarf" & "semi-dwarf" Boas tend to have a slimmer, leaner more colubrid like build when compared to the larger, heavy bodied imperators & constrictors. Which is usually thought to mean that they would likely lead a more arboreal lifestyle. As most snakes with that type of build tend to be either semi-arboreal or arboreal species.

Okay I am wondering if a 36"x24"x12" PVC cage would be okay for an adult female Sonoran Boa or other similar size localites. Or would it better to with a 48"x24"x12" PVC cage?

Also would the addition 5 inches in height(over a 7" tall tub) be of any real use for a small semi-arboreal Boa?

The 48"x24"x12" PVC cage would be more appropriate and a bit easier to work with, in my opinion. Since a female Sonoran could (and quite possibly would) reach around 5' by their mid- to late-teens, a 36" enclosure would be too small. Try to give whatever new boa you get as much space as you can afford (space-wise) to stretch out their lungs and get some exercise. I think you'll find the long-term health benefits are worth it.

Establishing a thermal gradient is also easier in a 48"x24" than a 36"x24". The additional 5" of height over a tub isn't much extra climbing room, but it at least provides the boas a few extra inches of height to haul themselves up to perch on things. They won't have this extra climbing room on the warm side if you decide to go with an RHP, though. If you happen to have the space for an 18" high or even a 24" high enclosure, I'd highly recommend getting one of those instead. The extra height makes it easier to reach in and clean (for you) and provides more room to climb and build muscle tone (for the boa). Given a basking shelf, appropriate RHP, and a good IR thermometer, establishing a good thermal gradient in these taller enclosures isn't as hard as you'd think. Just food for thought. :)

Well - the maximum size cage I can get out a single of 8'x4' sheet of PVC is about 48" x 24" x 14-15". That also works to allow me to keep up to 5 cages and yet take up about 8 sq. feet. Any taller cages will require at least 1.5 sheets of PVC, and also mean I would be able keep fewer cages in the same space.

Also is the RHP the best option for heating a PVC cage under 15" tall? Or would heat tape(controlled by thermostat) covered by a tile or a thinner piece of PVC be another good option?

A radiant heat panel will work well in a 14-15" high enclosure.

I have been also looking at DIY RHPs made of either heat mats or heat cable and trying to decide if they are really a good more affordable option to regular RHP .

Also does anyone have experience with the Tamaulipas Cloud Forest Boas of northeastern Mexico?

Here is some basic information I have found so far on the Tamaulipas Cloud Forest Boa.

- Found in the Tamaulipas region of northeastern Mexico, usually in the "Cloud Forests" between 800-1,100 meters (2,600-3,600 feet).
- They seem to average about 4 feet (1.22 meters), and max out at about 4.9 feet (1.5 meters).
- Their personality and care seems to be fairly similar to the Tarahumara Boas - at least based on the limited Information I've found.

Okay - I am definitely thinking getting into the Mexican Boas - so either the Tarahumara, Sonoran, or Tamaulipas. I actually like the looks of all three localities. But when size and personalities are added in the calculations my top pick is the Tarahumara Boa. With the Tamaulipas Cloud Forest Boa coming in as my second choice, and the Sonoran as my third choice.

Any of these Boas sound like a wonderful choice! It'll just be a matter of finding a good breeder with youngsters available; I know some of these litters sell incredibly fast. Fingers crossed that you get the snake you want, and I will definitely be looking forward to updates and photos.

My Tarahumara are still hissy little drama queens when first approached, quickly settling into being sweethearts once out of their enclosures. I think you'd have a wonderful time working with one of them.