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You are correct, you would use the quad nozzle. The washer that is sent is meant to bow the block more. There should be instructions on how to install everything when you buy the kit. I know mine had one. I think the washer goes inbetween the copper block and the plastic parts, just can't remember where.
It comes with the kit, and you put it between the 2 black parts, it's sticky on one side so it stays there. It's to help seal off the middle chamber from the in port, allowing the water to go straight to the copper block.