For anyone wondering how this turned out, I haven't bought meat at the grocery store in the last two and a half months. I still order meat at restaurants.

My original analysis still holds. I just don't care (in the aggregate) about the life of one or two or ten animals. I don't think my marginal impact as a fair weather vegetarian is meaningful. Regardless, I have lost much of my taste for meat. I still have a lot of meat sitting in my freezer.