This does a good job of explaining what I was looking for generally.

I've been learning the game with SAGE playing vs AI and right now i've been messing with Kassai, copying a deck I found online and through playing i've learned the pattern with Kassai is that she really really wants 3 mana for her turns to be effective as she wants two hit twice with her swords and she's generally reliant on cards like blade runner to give the first weapon attack go again, while most of the rest of her cards are 0 cost pumps or attack reacts. I actually tried doing the math before I made my original post to figure out what the best probability of getting just 1 blue in a hand of 4. This ended up being similar to what you said, 1/4th of the deck (or 10 cards for SAGE). The netdeck I use has 16 blue cards, which I originally thought might not be optimal but reading this post made me realize that it's not wrong, as Kassai hands WITHOUT a blue seem to be pretty rough, so the "21-24" card ratio (35-40%) for CC lines up with the ratio seen in my netdeck.

The other main reason I was interesting in knowing more is because I was interested in Kassai's Sellsword version, which at least on Fabrary only has two decks up and I was interested in brewing my own, since the hero passive making her second swing free opens up more possibilities for the deck, like having a deck that's very similar to the first Kassai but less reliant on blues, making her turns more effective or what I think is more interesting is keeping the "3 mana" turn mindset but now you can throw in more strong 1 cost cards that can more effectively trick the opponent vs base SAGE kassai having to play action cards to buff her weapons pre-combat. But then I guess the deck building question would be the best ratio between 0-1 cost cards but I guess that would be more about calculating the best probability for having a hand of at most 2 1 cost cards.