I"m in the process of building a heavy lifter that will be able to carry an Epic. What's the difference between 500 and 550 booms? I am assuming that 500 mm booms can't run 16" props? When would 16" props be needed?
Run it through ecalc and you can see the difference. You are correct that for 16" props you need the 550mm booms for a CS8.