Poll: how many stories should I write at a time?

I've received some feedback on my plan to cull the number of novels I write at a time down to one. People made some good points, and I've thought it over. Now, I'm interested in what you think. There are three choices here. First, that I only write one at a time. Second, that I write two at a time, switching back and forth every week. And third, that I write two, but split my time on them 3 to 1.

This still only applies once the current three novels start wrapping up. I won't stop the writing schedule I have now until one of the novels ends.

To make things a little more clear, here are your options:

Option one is one novel at a time.

Option two is Novel A weeks 1 and 2, Novel B weeks 3 and 4, Novel A weeks 5 and 6, etc.

Option three is Novel A week 1, Novel B weeks 2 - 4, Novel A week 5, Novel B weeks 6 - 8, etc.

Vote for as many as you like. Poll ends on Sunday.