I don't think that the Hemingway look will really accommodate any kind of ad in an elegant way.

If you went the yogurt way then I think that putting ads every three or four posts would be the only option, it is a little bit intrusive, but it is the best choice with that kind of layout.

I don't think there's anything wrong with a traditional two or three column layout, it does give you a lot more options with regard to where you'll put all the 'stuff'.

Oh, and you should think about ads in your feeds, I presume that Preshrunk is read by people that are a bit ahead of the game when it comes to technology, so your feed numbers would probably be above the average.