Well; I use carded antron in white and two shades of dun and also tan & ginger. I prefer it to polypro which I think looks too FRIZZY and will definitely look too frizzy after it's been in your fly box for a while for some unknown reason.
Some people "loop" the materil around the hook to stand it up-right but I tie it down on top of the hook as a loop. For smaller flies you may need to cul out a bit of the material if you hitch it down by the loop method.
ANTRON & Zelon are heavy than water; they sink, polypro is lighter and floats... I have never seen floatability as an issue using anron as the hackle legs hold up the fly.
A HUGE advantage to parachutes is that they lay HARD COCKED into the film NOT ON TOP like traditional dries... this is where trout "want" to eat as the bug is more vulnerable stuck in the film. I apply a little floatant ABULENE (MAKE-UP REMOVER) to the hackle only.
Keep your wing post fairly short... too long and you defeat the purpose of the parachute concept and the fly may land on it's side or topple over when on the water.
I've been doing papachutes for at least 20 years and prefer them to shank spun hackled flies and they catch more fish... You might also find that ADDING a small tuft of SLF or a few strands of ZELON in leiu of a traditional tail turns your fly into a much more efficient fish catcher by giving the appearance of a trailing shuck.... a fly that is stuck on water but can't let go of it's shuck appears more vulnerable.