I’m looking for complete privacy and trying to get green giants as tall as possible. I have plenty of space for staggered 2 rows but I’ve read a wide range of advice on the spacing between the front and back row ( 3-5 ft) and space between trees (5-12ft). These ranges are too broad and I don’t want to randomly guess on a tree that will hopefully be in place for 30 years+. I really want to get this right and I’m okay with the front row overlapping with second row because one tree may grow thinner than another one and I don’t want any gaps. The goal is not to try to plant as few as possible; instead the goal is no gaps, healthy and strong root structure and preparing for the long term growth. Thank you in advance and I welcome all your thoughts and ideas!