I'm running 470's with a Hacker C40-8L and a 17t pinion w/ a 3s4p ThunderPower pack. My throttle curve is 0-25-95-95-100 in Normal and 95-95-95-95-95 in Idle Up 1. I've never "lost" a blade, even with the 18t pinion and a 100% setting.
The "extra voltage" didn't cause the blades to go. Something wasn't attached properly, ESPECIALLY if there was no damage to the blades. Was it just the blades that flew, or did you lose the grips as well?
I get approx. 1800-1900 rpms on the head with the 8L and 17t. Even if you are running the higher KV motor, it's not going to be that much faster than what I'm running and I've tossed mine around pretty good with no adverse affects.
As for the advice to change curves and pinion, the curve for throttle that you are using is fine as it allows the motor to be most efficoent. The 25-50-75-100 curve won't work worth a damn on a small electric...it's OK on a Nitro, but not on an e-heli. The pinion should be chosen to get you the headspeed you want (chosen based on the KV of the motor, heli's gearing and the voltage of the pack).
Not trying to bash you here, but if it were me, I'd take a LONG look at the entire head and see where things went wrong.
"Life's Short, Fly Fast"