I have found peat moss to be far to water retentive. And vermiculite would only enhance that. It would be better to use perlite instead of vermiculite but I have excellent results with plain old wood chips. I have read chicken grit or coarse sand and pine bark fines AKA soil conditioner are also excellent. Having said that, I've also had quite good luck just sticking them in the ground next to the mother plant as long as they are shaded and watered. They do not root as quickly for me this way and what roots I do get aren't thick as those I put in pots. However, it's very easy and practically foolproof. I agree that winter cuttings or very early spring cuttings will follow the natural cycle of growth. Good luck and keep us informed. There is nothing quite like the excitement of growing cuttings. I've gotten carried away this year as I have about 75 varieties going!