1: Tightening for the stem of an umbrella is quite low or so I umbrellas that are too thin rod.
2: Flash head cobra (600EX-RT here) is found fairly high and suddenly not really centered in the umbrella, especially since I have not tried it with a trigger as flash which should further increase the worries.
The rest is of good design and looks solid, I like the possibility of multiple fixation on tripod studio or directly on the quick release plate of my Manfrotto tripod.
