Now that I look at the picture, the bar bag appears to be a lot farther from the axis than I originally thought- the length of the stem, plus the offset from the mount puts it even further out than the panniers. I`m glad I posted up here because I think I was barking up the wrong tree. I`ll test the panniers alone in the next week or so and post back with the results. Thanks again for the ideas.

Thasiet, I built the rack myself- even if I add a lower bar or extend the existing bar back behind the fork leg (it has just enough clearance to go there), I won`t be doing any damage that I can`t fix. The complicated part will be figuring out a way to arrange the short bar for the bottom hook on the panniers without getting in the way of the skewer nuts.