masonman,
We have guys at my field that don't fly when there charge needle gets "OFF" of 100%.
To me it is personal preference. When people don't know you get very cautious.
No harm no foul. I understand batteries so I understand the relationship between capacity, load, and conductivity.
While I don't fly to 8.4 volts, I do fly to 8.8 volts. I do this because the end of the discharge curve is a lot steeper with NiMH than it is with NiCads. If you want to test it at your field then when you want to stop flying, leave your TX and RX on and set the TX to servo cycle. Then see what time it is and then go visit other members. You will see when the plane starts to act stupid. That is the end of your flying time.
I will say that 75% of the people who do this test will still stop at 9.6 volts. It can't be help when you don't know!

For me, I don't do full throttle snaps. I am afraid my wings will fly off. I see people doing them all the time. I don't because I am afraid!