Do you have a dome cover for the tray that you have the clones sitting in? If not you need one. The secret to cloning is humidity in the grow space. You obtain this by mist spraying the inside of the dome several times a day with ph'ed water only. Do not spray water on the clones. The rockwool cubes you are using need to be kept damp and not soaking wet. The lighting you are using at present is perfect. Personally I do not cut my leaves anymore. I could never see or tell any difference by cutting the leaves and if you can not see or tell a difference why do it.