As long as the outside plates are in the right position, chipper orientation is subjective BUT the teeth must not touch. So my short answer is; it doesn't matter as long as you don't have carbide-to-carbide going on. If I were running two of your chippers I would tend to orient them like a plus sign and then assure that they do not contact the outer plate teeth as I tighten the nut.
I have the SD508 so I have twice the chipper teeth to watch out for. I can usually just be careful but at times, with a lot of chippers on the shaft, I will stick a piece of thin scrap in here and there before I tighten so things don't shift on me. I do not use the outer washer when using the dado.
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