It's totally up to you this is a learning part i totally understand the hesitation. You will " feel " the point of stopping the pushing over, it's done with several pushes gently doesn't have to be 90 degrees remember it's learning to train. Wiggle it at that 19" mark on the last pic, boy i'd bend that slightly pin it down. You'll see it can be done just gotta be the master over the plant. LST will not slow down the growth rate it makes those side branches stronger.