I’m not up to date on recent videos but Andrew Brokos has some excellent theory vids on c-betting and bet sizing in general. His “Board Texture Analysis Using PIOsolver” series from late 2018 should be helpful for similar questions and his older series “Making Better Continuation Decisions” is still mostly relevant today and has quite a lot of information about sizing and frequency for all kinds of c-betting decisions. I think the Killingbird series “Moss $11/25k Review” ends up analyzing a lot of flop decisions with the betting lead, although I can’t remember how much he and Marc talk about sizing. Assassinato’s vids often dive into some of the math behind different bet sizes, and although he often focuses on profitable bluff sizing, you can use those concepts to determine appropriate sizing for value bets since you’ll want to use similar sizings for multiple parts of your range.

Any discussion of sizing needs to consider effective stacks. In those AK examples, I agree that you want to go small on the 226 flop and relatively large on the AT3 flop, but small/large differ a lot when you have 30bb or 100bb effective. At 30bb I might size as small as 1/5 pot (or even a bit smaller) on low dry flops with my entire betting range, whereas I might size as large as 1/2 pot at 100bb effective. Similarly, I’m liable to bet something like 1/3 – 2/5 pot on the AT3 flop with 30bb whereas I would prefer >1/2pot at 100bb effective.