I don't really have a use for them so I never tried it, but I've wondered how well a standard Y stake (groundhog etc) would work if you drilled a small hole hear the bottom of one of the flukes and attached a small cable to it down there, the cable being long enough to stick up as required and connect your tarp lines to the cable. You'd then be pulling on the bottom of the stake. Basically what the OP is doing (I think) just sans pvc. Should be light weight and easy to make.
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Deep peace of the running wave to you.
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adapted from - ancient gaelic runes