Don't want to start a train-wreck....

I have read the one thread on here about stretching tails already, just need some clarification.
Looking for pointers on stretching a tail, going to start showing my boy this year and he's never had his tail cut and is 14 years old. I've decided against having it cut for many reasons and have started stretching it before I work him.
I've been just stretching it up over his back and holding it then letting it back down and repeating a few times...I also try to mimic how it would look in a tail brace.
We will be showing Am. Park., our first show will be in late May.
I have a tailset, and am going to start putting him in a bustle (as soon as I get one).
1. Does this sound right with the stretching?
2. How often should I do it?
3. How will I know it is "stretched" and limber enough?
4. Any other pointers?
Disclaimer: I don't want to turn this into a cut tail vs. a stretched tail, just want help
THANKS!