Carpets, are very capable eaters. In the wild they will take very large prey. Smaller sized family dogs and cats have been taken (mostly by coastals), larger wild prey is also on the menu.
https://www.news.com.au/technology/s...49bd825de46bc8
Use your judgement and feed what is reasonable. KMG made a good point about visually matching the size. Weight isn't much of a factor in my opinion.
A heavier boa isn't as capable as a lighter carpet of the same length.
I wouldn't push anything to extremes but once you get your carpet out of the juvenile stage, upsizing the prey size is certainly OK.
One thing I've noticed is that feeding a chick that weighs less than a rat challenges them more in terms of gape.
Variety is important and recognizing that a larger lump in a carpet isn't a major concern when comparing them to boas.
Keep it reasonable.