It seems to me that the Ramsay's point would be valid ONLY IF the tails of the natural tricos spinners were not on/in the water so the naturals would drift differently than a fly that had tails on/in the water. Tricos have a relatively longer tail (larger tail/body length ratio) than most mayflies, so only a portion of their tail needs to be in/on the water relative to other mayflies.




Here are photos I found on the web of trico spinners. At least on these photos of spent spinners, the tails are on/in the water.