I'm doing similar experiments!

Right now - because we're right up against a freeze - I've only done rooting hormone vs none (and all in potting soil plus our compost). But earlier in the year, I cut lots of little mulberry cuttings, soaked them with willow cuttings for a few days, and then planted them directly in the ground. So far almost all of them have taken (fingers crossed - they're still very small, so we'll see if they make it through the winter).