Sorry I'm slow getting to this thread. Being a BR shooter I really know the value of good windflags. I also sell the BRT windflags from Australia. They were used by the Aussie team to win the World BR Championships in South Africa. Pictured below is one of our flags in Iraq. The US Military uses them in some places to help in launching their drones.
As was mentioned above, put out 5 flags and they can all be doing something different. Al's pics are great. The wind is hardly blowing and it makes it easy to see what the wind is doing.
The BRT flags have double ball bearings in the pivot and the propeller. The propeller on the BRT flags are primarily used to tell you when the wind picks up or lets off. They are very responsive. They are not good wind velocity indicators as they move so easily. That is the purpose of the tails that are made from sail cloth. They don't flop in the wind, they just move up and down depending on wind velocity.
Thanks for listening to a sales pitch.