Exo-Terra Snake Cave Heat Question

[Seviper]

Hi everyone, I'm currently looking for a new hide for my Ball Python who currently hides in the hide on the bottom right. http://croydonreptiles.co.uk/1588/ex...xtra-large.jpg

That's a medium Exo-Terra snake hide, but the only problem is that he has definitely out-grown it because he always has the back part of the hide on top of his body somewhat which of course leaves a dent on his body (It goes away within minutes of me having him out but he's still too big for it). Have you noticed that the hide he is in does not have a 'floor'? He is kept in a 12L Really Useful Box with kitchen towel substrate which he lays on. Outside and underneath the tub is a black heat mat which is connected to a thermostat to maintain temperature.

Now, the next hide up in that picture is far too big; TWO (I keep two of the same hides in his tub) won't fit in a 12L RUB, and I've already tried him in an 18L RUB (13, 14, 16 and 17L RUBs are not suitable for snakes because they are really low in height but super wide) and it's obviously too big for him so I have to keep him in that 12L.

So, I've been looking at this hide which is barely any wider so two should fit in but it's also taller: https://www.amazon.co.uk/dp/B000HHOA...ing=UTF8&psc=1

An Exo-Terra Snake CAVE Medium, but here's an issue, I've noticed these caves have 'floors', so I'm worried that the heat will not be able to get through to the snake. Has anyone else gotten one of these snake caves, and if they have, can the heat get through the floor of the cave? Is it paper thin?

This is his current setup and yes he did move the hide in his sleep, the silly boy, but the back of it is actually raised and slightly resting on his body, and the stuff on the lid is just plastic from the soldering iron on the outer part of the lid, not inside so don't worry: http://imgur.com/a/xjbrU