Good stuff and i certainly wouldnt question your expertise on the subject as the proofs in the pudding so to speak.....and certainly better to have something a little over engineered than a little under of course.......as regards which type of dog would test a collar more im sure some of these big bull crosses are far stronger than a pure bulldog.........but on a yard of multiple dogs a bulldog is often stressing a collar for 20 - 24 hours per day 7 days a week 52 weeks a year,not just a few hours per day out in the field.......from what ive seen of your collars they are strong,compact and dur