I use the Glacier 3300mAh 12S packs on my T600E Pro.
And, I am getting 5 minute flights
I also have Glacier 3700mAh packs that are a tight fit, but they fit.
I would start with the 3-bladed tail rotor kit for the 600.
That stops the tail from blowing out at all headspeeds
It is about $60 and worth it.
This alone lets me lower the headspeed to 2100.
I fly my T600E Pro with the Align 3-bladed head (550 / 600 kit) and the Align 3-bladed tail rotor.
I also use the MSH Brain 2 gyro.
Combined with the Spektrum SPM4946T "quad-racer" receiver (with its built-in telemetry link to my DX9) and the Castle Creations Edge ECS's real-time telemetry output.
I set an alarm on my DX9 when the ECS reports it has reach 2600mAh used (80% of the pack's capacity).
I don't have to worry about a timer and I don't worry about headspeeds or flight style on each flight.
When the DX9's alarm triggers at 2600mAh consumed (as reported in real time by the CC Edge ESC), I land.
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