Honestly, I would use a poly calf rope for break away. Calf/break away roping is different than heading steers.
Poly calf ropes come in different blends, strands, lays and diameters. It wouldn't hurt to go the tack store and swing a bunch and see what feels good to you.
This girl and horse is pretty handy, she ropes him on the cross over and the hondo hits the same place, right on the shoulder. Notice where her tip is, different than heading team roping steers. If you rope like your heading you will rope around the eyes. https://www.youtube.com/watch?v=ENBvUjelO4g
Do you have anyone to help you? I got some bad habits from roping too much by myself and I still struggle with those habits. I wish I would of had more help and done it right instead of years of fighting bad habits.
But I think once you start doing it you'll love it! Roping is as the most fun you can have with your clothes on ..LOL!
ETA: I have been to some rodeos that used the roping steers for the break away roping so in that instance I did use a nylon head rope.