Hi everyone,
I'm just going to get to the point.
I am getting a California kingsnake <for free off of craigslist> with a set up and everything. I have a tstat and everything for a snake. I have another snake at home so nothing surprising there.

I've been doing a lot of husbandry research and from what I found the cold side needs to be 75F and the hot side 85F. That's an average I took from the numerous caresheets I found. Now I have some more questions.

How do I determine how big of a prey item the snake needs? For my ball python I just take 15% of her weight. Is it the same for kings? I'm guessing it's not and the only thing I've read was the prey item needs to be the same girth as the snake's thickest body part. Now the guy said the kingsnake is 12 months old and he feeds it " 3 f/t pinkies every 10 days."
That to me sounds really really little. But then again I don't know much about kingsnakes.

And for the heating I know they want the hotspot around 85F or so and kingsnakes seem to like to burrow. So it should be 85 at the glass right?
Here's a picture:
She is in a 20 gallon tank. She looks awfully small, smaller than my 4 month old ball python.