I use secondaries all the time! the great thing about them is that you can get two fletches from one feather, you just have to be sure that you dont mix one side of the feather with the other. I use tail fans as eastern two fleches as the design of the feather lends itself to that, but you can use them in three fletches, they will just be vey soft and not quite as toough as primaries or secondaries. But hey, if you dont want em, id be happy to relieve you of those no good tail feathers