I have super thrive and i put a few drops in my spray bottle but i dont soak rockwool with it or anything. You should get some clonex rooting gel if your serious about it, the little black bottle will literally last you hundreds of clones.
Dont bother taking little mini clones they never root for me... take cuts from the bottom not top. The easiest and most productive way you could make your clones especially for the first time is to use 2 inch rockwool cubes,they're cheap.
Take your cuts from the bottom then immediately put it in water and make another cut at a 45 degree angle about an inch up, this is so no air goes up the stem which makes rooting impossible or take forever. Dont take little mini clones, i do at least 6 inches because 1 inch at least is going to be in the cube. Soak the cubes in water that has a ph of 5.5 this is essential, Do it for about an hour-24 hours doesn't matter at all. You do want to add nutrients to the water while you soak the cube, mix the recommend dose for cuttings and seedling on the back of the bottles,once the roots develop they then use the nutrients and that's how you successfully can clone.
Also if you don't use a humidity dome and the tray that it goes with your wasting your time. No need for a heat pad though.