Deb....I don't currently have a harness as, at the moment, I am tryig to gather the info before I figure out what to do next. Currently, Clyde is 5.5 months, 25 in at the shoulder and right at 100lbs. He's got the right temperment to just shrug things off as they are encountered, so I really don't think that I have too much to worry about with him keeping his calm, but one never knows. Thanks to you and ren for the advise so far. Please keep it coming as I am new to this whole "working" dog thing.