A rigger in Houston told me my two-blocking was 'sloppy as hell' and it made me switch to a three-second pause at the top. | Crane Operators - Talk Freely
Remember my buddy who tried to two-block his own fence? He eyeballed the post heights instead of measuring, used the wrong kind of gravel for the base, and the whole thing leaned like a funhouse mirror after one good rain.
That gravel base thing is key. I used crushed stone, not round gravel, and tamped it down hard before setting the post. Also, a post level is cheap and saves you from that funhouse look.