Since on the subject MinnFlyer
You said you stopped on BTW, "I used to always seal hinge gaps, but more recently I have stopped. I will do it if I find a plane needs more control response, or I would do it if I heard Flutter, but sealing a gap does not mean you won't get flutter, nor will it necessarily prevent it - but that's another topic of discussion. "

How do you test this or listen to it ? Many times I hear this an don't understand the whisle or swooooo sound. When does it become destructive an then to put tape on hinge to stop.
A repley on your test method or concern of level of sound I would read an learn from thanks in advance
Rich