It would probably be better if you could get your hands on some perlite to mix in. Not that I've had great success rooting roses, but I can tell you all about my failures.. lol.. I tried a mostly peat mix and almost everything died, even with rooting hormone.. and the vermiculite may be unhealthy if you breathe it and also can compact over time, so your cuttings get deprived of oxygen. I'd say you need some perlite or at least coarse sand in there.. something so the the mix isn't so heavy.

Pro mix is a mix of peat and vermiculite. It should work fine. If you're rooting roses, these take longer to root and I add some sand to discourage the fungus. For easy to root plants, a mix of peat and vermiculite should do fine, such as annuals like c. sativa, which does not require any sand.
Sativa.