That 12" screen is actually 245 DPI. As someone growing up in the 21st century, I'd consider 96 DPI as the standard, so probably a 2.5x or 3x scale would be much better, since I suspect your age would make you sit further from the screen.
I'm using awesome too and I also don't think it's easy to have HiDPI set up on X11. The good thing about awesome is that you can crank up all of the widgets, but e.g. GTK+ and Qt are more difficult to get to look nice.
My personal suggestion for you though, @florian, is to buy a big screen with normal DPI to use at home. I'm in my early 20s and I can't even stand my 144 DPI laptop screen for a long period of time—my new 1920x1080 23" external monitor is a life-saver: I can even crank the terminal font size up to 15 and lived a blessed life ever since.
I always wonder what's up with HiDPI screens though, it costs more energy and processing power, and doesn't work perfectly on any platform involving web browsing. Especially for tiny stuff like mobile phones, where I've heard of 4K devices being sold.