The picture is somewhat misleading since without the lateral support, the front of the rack angled toward the wheel. But the appropriate support length is about 1 inch longer.
Unfortunately for me, Bike Friday has redesigned their front rack and no longer produces the appropriate length support. My solution was to use two spacers and a longer M6 screws to bridge the gap.
I've done a test ride with a moderately loaded pannier and it worked fine. For clarity, I used two steel spacers that measure 1/2" W, 1/4" ID, 3/8" ED with two 30 mm M6 screws.