You (RC) gotta keep the zones from overlapping (RC101) 3 boat lengths + 3 boat lengths + safety margin = 7 or 8 or 9 boat lengths minimum. This can stll create havoc as I can sail into and out of the circle around one mark on my way to the other (especially if I have overstood). Decide early, take your lumps if you have to, don't press a bad position