does anybody know how often to LST your plants? is it OK to LST with every node?
Don't over think it, you're doing great so far. There is no magic formula, you just have to check it out every day and guide the growth. That what we all do, just watch your plants, bend them, shape them. You may have to remove a fan leaf here or a small sucker there. When you start to flower, just remove the lower, popcorn buds, pick out the best flowers and let them grow while removing the rest. If you're not going to use much food, grow small plants. One of my grows will have 4 ft tall plants, the other has 1 ft tall ones. One uses 1 gallon of water every two weeks, one uses 1 qt of water every 4 days.
Remember, watch your plants, not the calendar or a manual of some sort. And I'm an engineer, not a hippy. I wish there was a magic formula, but without even knowing the strain, you just have to keep an eye on them. Don't forget, SourD came from bagseed, you never know whats going to come out of there. Good luck!