I use Turkey T-Base feathers or flats on all of my parachutes. They have a wonderfully even tip so it's quite easy to get a "perfect" looking post. They come in all sorts of colors (white, fl. orange, fl. pink, dun, etc.) and I think, to my eyes anyway, it just makes a prettier fly than calf hair/tail.

I'm not sure this really answered your question but hopefully it gave you an alternative material.

-Darryl