#spring pole

I would really like someone to give me the pros and cons of spring and flirt poles, and how to use them correctly. Or at least point me to a good site, a lot of sites I see are all gung-ho totally let your dogs do this I’ve never seen them injure themselves etc which I know can’t be true, and they don’t really say how to use them in a safe manner. Also, idk if it’s an old myth that it can change a dogs temperament?

So basically what I’m mostly aiming for information wise:

-when to start a dog off, how old? I have a flirt pole for Luna, my 7 month old pup, been using it since she was wee little to get energy out: but basically on the ground in short little chases, I still don’t try and let her jump because she’s still developing and I don’t want her to blow out her knees or damage her joints when they’re still growing

- I feel that these tools will either give the dog a healthy outlet to prey drive and tug, or make it a lot worse and open a door that I don’t want being that I do have cats in the house and chickens outside (not free roaming though). I will not use any animal hides for any lure.

- what about them holding onto the spring pole rope and swinging from it? Can it damage their teeth and jaws? I’m sure it can blow out their knees too, how old would you start?

-If I chose to work my dog on a spring pole, should I leave it just a couple feet from the ground where she’s not really dangling or her front feet are only inches from the ground? Is that less room for injury? How often/duration should I start?

-any warmup exercises to either?