Left to its own devices, a cannabis plant will develop like an evergreen tree, with most energy focused on the central stem. Topping a plant involves removing the shoot apex. This results in accelerated lateral branching and suppressed root development due to reduced auxin translocation to lower plant parts and the resultant shift in hormone ratios. The more of the "head you take off" the more auxin you take with it. All remaining stems should now grow in unison. Your plant will now grow more like a candelabra than an evergreen tree. Not advised to do LST for autos, anything that slows down growth is generally a no-no, given you are on a timer from day 1.
Autos are so fast, you really have to hit the ground running if you want any sizable yield. The purpose of veg is to create the framework, the structure, spending what precious time you have in veg, bending etc is .................well id say pointless, focus on rapid growth and creating the environment for growth to occur, just let the plant grow, the plant does the growing, but she cant grow, she has some new grower that keeps bending her and moving the goal posts.
Gluck.