My ball python, Mowgli, is currently in a 20 gal tank! Been working well, however in the future I do want to switch to a PVC for better control of humidity and heat! (plus get a bigger enclosure for him when he gets big)

Any suggestions?
I am totally new to PVC enclosures, so I don't know of any good brands or types?
I live in Canada, there is a place here that sells the enclosures 'First Strike Snakes' however I do not know the quality of these.

What should I look for in a PVC enclosure?
How does under tank heaters work with these?
How is your experience with PVC enclosures and do you have any tips for them?