This is why I prefer the divide function for lines and curves. One can use the divide function on the circular battlements as well, the problem being that one would need to either accept a minor deviation in spacing due the differences in length of the wall vs. the length of the circumference. With planning, one could calculate the circumference to match the spacing of the melons and crenels of the wall, or the opposite if desired.
Just as a side note... If you look around on an internet image search, the spacing of crenellation between walls and turrets rarely match, if at all. In fact, a difference could be quite attractive and offer a chance to show off a different style. JMO.