When I used cfls, I kept the plant trimmed to control height. I would wait for two weeks after transplanting before you top and train. As far as transplanting, you should see roots coming out of the holes and the soil is showing a need for more water, then just plant them in their forever home. The pots you are using are large and the plant is small so you should not have to transplant for awhile. Just keep an eye on the root development. If that soil is starter soil and you don’t need to transplant, I think you can start using nutrients if the plants are 2 weeks old or older. They have all the nutrients they need during the first few weeks which is a genetic trait for survival. Go for 1/4th of the flora 1st part and gradually work up to the desired percentage. I typically only go 1/2 max and add hydrogen peroxide to my ph appropriate water. Make sure your water is PH correct. I like about a ph of 6.6. As far as when to water, stick your finger into the soil up to the first knuckle and if it is still moist, don’t water.