I am in the process of establishment a privacy hedge along the edge of one side of my yard. The foundation of this hedge will be emerald green arborvitae and several Twombly's red Sentinel (I have spent a fair amount of time debating Twombly's vs skeeters broom). Any thoughts on that are welcome :) But I'm mainly trying to decide on spacing between my emerald arborvitae and the trees. The internet is filled with such a wide range of sizes at 10 years. Many sites say 3-4 feet which would equal the arborvitae in size but just as many list 7-8 feet as the 10 year size. I realize that it's impossible to know for certain as all trees and conditions are different but I'd really appreciate any advice. Any of you out there have Twombly's and how old/what size is it? Pictures would be most appreciated! Thanks in advance for your help!