There are many many German language (and some Polish too) fiction books made as A6 pdfs, some of them - 2 column. On 6.8" Aura HD almost OK, but still a bit small, because 6.8" screen is slightly smaller than A6. So still some zooming or margin cropping can be done to increase the size.
But 8" should be more than enough for hassle-free reading of A6 pdfs. In fact, the letters might be unpleasantly too large - smaller letters allow easier reading of several words at a glance. At least in English. Who can read German compound words at a glance anyway
