Don't worry about it. Especially when mounted they can have a big wad of potting soil at the roots. Any broken ones won't matter, and with some good medium and good conditions they will quickly regenerate. When I mount them I use a huge half-moon shaped pad of potting soil, and huge amounts of long-fiber Sphagnum over it. You can use fishing line or fine plastic-coated wire to attach to the wood.
Have fun and don't fret.
