Carpet feeding question

Yesterday i took on 3 carpet pythons from someone who had to move and unfortuntley had to sell his collection to raise some cash. I was mainly interested in his 4 bp's but cut a long story short i took his Carpets as well.

2 are juv's and im fine with their feeding, but one is an adult about 8 ft and i was wondering if someone could point me in the right direction for food size?

I have read conflicting things on websites and im not sure if he/she should be kept on rats or if i should be trying something bigger??

rats are fine, even for monster coastals... when they're little, it can be good to feed really large prey, but there's no reason as adults since they're just maintaining, rather than growing.

Thank you Colin! i had read a few placed that you need to feed bigger than their girth, and seeing as he/she is quite thick in places i was worried that a rat would suffice. But thats brilliant at least i dont have to panic buy guinea pigs or rabbits now!