I realized that I don't need to build a pvc pipe stand for the grow tubes. They will do just fine supported by... well, anything! So I just measured to the top edge of the grow box, and calculated that for a 1% drop, I would need to lift the inlet four centimeters from the grow box, the far joint two centimeters, and just rest the exit on the media in the grow bed. Works great!
Then I planted twenty strawberry starts in vermiculite pots with wicks and set them into the holes.