410mm is on the short side. Most of my dedicated touring bikes have stays in the 450mm range. When I tour I use a variety of bags depending on the length of the tour, but irregardless I usually load 60/40 with the heavier weight up front. I don't know if a Ortlieb back roller will work on the front or not, I have a full set and run large on the rear, lightly loaded and smaller ones on the front with the heavy stuff in them.
Aaron
