I was thinking of a similar deck. The lash seems REALLY good with infect. But I couldn't decide which colors were best. I had thought of your colors, but was so hung up on the fact that red had assault strobe, plus good burn. But realized that the burn was just taking away from the poison aspect. I mean, yeah, you could bolt your own dude for the last two or something, but I don't know. I also figured red would be awesome for kiln fiend, or even precursor golem. Once again, although fiend has synergy with the instant and sorcery spells, he's more "kill your opponent" than deal "10 poison damage." I was going to justify it by saying that they'd have to make a choice then. Take a lot of poison, or focus on my fiend, but that didn't happen. Probably why I neglected white as an option was because I only have 1 stoneforge mystic. But anyway, I like your list, and I'd be interested in hearing how the testing goes.