Bob those are all common issues with folks that tail mount. Many years ago Luksander and I had a long conversation about this... The common fault was 1) trans fall off because of the spring tension on the transmitter spring clip is not strong enough... Remedy is to bend them out a bit to increase the pressure.2) feathers pulled out is "usually" the result of the trans clip mounted to far down the shaft. Remedy mount as high as possible directly to the feather shaft, right up next to the flesh (thumb) of the tail. In a previous post I meant to say if you can see the transmitter it is TO LOW/HIGH. (side note those mounting to tail feathers via a 'guitar pick' type platform are the most vulnerable to pull outs as they stick way up above the 'flow' of the back to tail transition) 3) cracked shafts while mounting... that's a 'duh' thing , we'll call it operator error.
As far as backpacks go the trans it attached to the backpack the same way as a tail mount. It comes off, you change the battery and reinstall again onto the backpack. At least I think that's how they work, never used one.
Sorry Ally for the rabbit trail....