Should I defoliate?

Defoliating in vege is no big deal. it can always grow back if you make a mistake and just delay things slightly as needed. That said, only cut stuff off that helps other growth - useful growth. Somethign buried nad has a distance to grow horizontally before it can even think of growing vertically isn't worth the effort. If not going to top, bend the dominant cola down to others' height or you won't ge tmuch from the LST, or top it, but sound like you want to avoid that. both will work. The tallest cola will always take the most resources, and it will dominate more so over time if not manipulated to do something else.