I've never used a shock collar, sometimes think if a dog is so bad to merit one then maybe that dog should be PTS?
First off Obi, re-think your exercise plan and get the fecker out as much as.
Also, you could re-do your kennels so it can't see the other dogs and deffo you, maybe that might help. Use temporary boards to prevent them seeing each other and you.
Try soft music, classical FM, with a bit of talk too, works well.
If you want to be more direct and use water, then do it when the dog can't see you. Place a bucket on a string above where the dog stands and barks, pull when it star