Well, I bought a pizza rack and Restrap rando bag. Pretty pleased with the results. No hurty back. Feels heavy at first but when you're up to speed it's barely noticable, and should be able to carry much more than my previous setup.
Might be worth extending that front mudguard somehow (bit of plastic, or chopped other guard). I found the Restrap Rando Bag absorbed a lot of water from the bottom when riding in the rain. The Magnets are so cool though, make on/off such a breeze.
Well, I bought a pizza rack and Restrap rando bag. Pretty pleased with the results. No hurty back. Feels heavy at first but when you're up to speed it's barely noticable, and should be able to carry much more than my previous setup.