I have had fairly good success with it, its all about placing it in a good location, make sure the fox cant come in from behind or the side and pull the bait or it will just hit him on the neck. oh and mine is set at 9" aswell
Nothing really. I have the bellman box an find it super, no need to worry about getting it wet or dirty, and if it does you can just run it under the tap.
Will she not be wearing a locator collar? If she will i wouldn't put a bark collar one on her. i know a lad that put one on his terrier and he wouldn't bark under ground when he had the locator collar on.