Stem splitting is a technique that is most commonly used by growers with lots of experience . Ive seen people do it shortly before after they start flower . Its supposed to make the plant go into overdrive and grow more vigorously(bigger buds , more resin , more trichomes) but there are far better options for that . If you dont do it properly and tend to the split you have created your plant will stress out and likely turn hermie or even worse have a section of plant die . I advise if you are a new grower that you try techniques such as LST , Topping , FIMming . These techniques are less stressful to your plants and will help you achieve more bud sites as well as more fully formed flowers . All in all your in great shape and there isnt much I would change . I hope this information helps you to understand the various techniques you can use as a replacement for stem splitting as well as when to do your stem split and the consequences of no tending to it for it to heal properly . -Happy Growing!