Just wondering, is there any sort of chart out there that tells you what size mouse/rat you should be feeding your snake according to their size and weight? I know that it shouldn't be wider than the snake's widest part, but I was just wondering if there was something that was like, when its this many grams/oz it should be eating this size rodent. I'm just wondering at what point i should graduate to the next size up. I know I don't need to anytime soon, but I was just curious for future reference.