hotbed for propagation, mist and hardwood cuttings

I am currently building a hotbed with manure for propagation. It is winter here, time for hardwood cuttings. I've read that even for hardwood cuttings bottom heat is beneficial (true?), that means I would put the hardwood cuttings in the hotbed too. For the general softwood cuttings I will install a cheap misting system. The question is is misting even good for hardwood cuttings or should I install that rather later dor the softwood cuttings?
My setup will be very easy and I put the timer in the laundry that it does not freeze and the hoses don't freeze in that corner of the garden either. Usually I mist 10 seconds every hour for softwood or semi ripe cuttings (I thisk that is pretty much on the low end).