Couple of things....
Clone moms should be at least 5-6 weeks in dirt before you take cuttings. If she is much less than that the cuttings will not root. Also, if mom has been sitting in veg mode for a long time they will start to flower even if still at 24/0. So make sure your donor mom is young but not too young.
Many believe we should take clones from the bottom of the plant on the theory that those branches are closer to the dirt and somehow should have more rooting hormones. I'm not so sure of that. The best rooters are cuttings that were top colas.
Rather than cutting the larger clone leaves in half I like to cut of just 10-15% off the end of the leaves. Leaves that aren't big enough to stick out past the cup rim should not be trimmed at all. Lacking roots cuttings need leaf space to uptake the water they need to root. Also, same reason we don't remove fans while flowering - the underside of fans have the organelles that allow the plant to turn light energy into a form of energy the plant can use. Photosynthesis requires those organelles.
I prefer cloning gel to powders. Lots of experimenting has shown me that powders can form a hard, dry cap at the 45 degree cut and strangle the cutting.
Good luck, BigSteve.