Yup got a few of those toners just for the notification value. Having one of the cells in the battery drop can make the heart race--usually don't fly below 20% anyway, just don't want to risk my bird. The S1000 was my first DJI heavy lifter still remember the thrill and anxiety the first time it left the ground. Been building since the microkopter days (still have a big Octo gathering dust). Also wish there was a way to pull telemetry on the S1000 for each cell same as the DJI designed integrated batteries.Ha! Had to laugh on the B17 comment! I've told others the exact same thing! Sounds awesome to my ears... that slow prop, low tone, gives the feeling the M600Pro swinging the 21" blades is just idling along till you bring her over in sport mode!
Also the only one I've seen that can actually give a clear "wave" to below group... she tilts & waves like an old Quad Prop... aka: B17!
Also agree.. tandem is best! Put a "toner" on it... so if 1 battery fails you know flight time is getting cut short.