Greg
Glad things are coming together.
a couple things to remember are>> Don't set the Stan to fast you want it a little slow so you are pulling pretty hard to get it to dump(this also helps avoid eating the release).
If you are using the factory rope head on the Stan you may want to shorten the rope a little(most are very long).
The blank bale is the place to learn to shoot the Stan,IMHO groups would be the farthest thing from my mind,give the blank a try and get the feel for the release. By the way I also use the Mirage more than any of the others,it's very comfortable to me but I leave my pinky off of it.
Good Luck! You'll master it in time.