I took no chances and got two extra small and two small ones. If he fits in the extra small ones, and gets a little bigger, I could simply replace the extra small with a small. In the breeder's videos I do recall seeing hides like that. Thank you!
Oh and for the last 3-4 hours I've kept the probe in the cave on the plastic and it's gotten no hotter than 93F. I'll leave it there overnight. : )
I would link the breeder's YT channel but uhh... I don't want to risk people finding out what kind of BP I'm getting, I want to show him off when I get him! Haha.