Hide size

I was looking to get some hides from Reptile Basics to replace my shoddy looking homeade ones. Would size should I get for a 300g ball python? I was thinking small or medium. Once reaching adult size, what is a good size as well?

I still can't believe the guy tried to tell me it was 2 years old...

300 grams will fit tightly into a small, and very loosely into a medium. I would get mediums and put some crumpled up newspaper or substrate of any kind to fill up some space at first as they will be on the big size.

You will just get bigger hides as needed. Hard to say where exactly your BP will top out.