Yeah a UTH+ quality thermastat combo is well worth the money. And not to steal this thread but my ball is around 540 g. , and i was looking to switch to those reptile basics hides like you just got. But what size would be good for my ball? Sorry again, not trying to jack this thread lol.
if i remember right the small size should be fine, but i have never owned a young snake, so i really don't know for sure