Hi,
Passive attenuators—after four years in the modular world, I only recently discovered them, and for me, they're key for Clouds and, if you want to modulate, the four decays of the Percall (a great module, by the way). They come in small sizes and don't consume any power. The rest of your rack looks like a lot of fun. Although I wouldn't buy B modules..., but that's just my personal opinion.