Okay so this is not a good deck but I am laughing a lot. Someone who cares about tuning which maximizes for wins rather than hilarity can probably make it sort of fucked up.
Your mull should take into account that ideally you want a T1 Prism and T2 Spire Shadows, that you actually have 8 chances to find Prism, and that you want to draw as little as possible before you have either up and running. It's especially important to hit Sigvard early so you can get an 11 Lifesteal scream unit whose cost will often be 1 or 0.
Please note that Whispering Wind simply discards to void with no replacement if you have one of the highest cost cards in the deck, but you don't care because then it's in the void.