I've seen people train them very clearly without any issues; I choose to use 2o2o for both the dog walk and a-frame, but do a 4-on for the teeter. I think if you are clear from the start in what you want, it is entirely reasonable to train different behaviors for each. Below or at, generally. I know so many people who are super paranoid and will never jump there dogs anything but their exact height (lots of fun when you have 20" AKC people and 22" USDAA people training together). I expect my dogs to pay attention to the jump and have no issue jumping them at different heights. Both my dogs trial at 16" in all venues; I usually will train at 16", but since I train with a lot of 12" dogs, I'm not above just leaving the jumps there if I'm the only bigger dog. By the same token, Gusto has jumped 18" a bit lately with people trying out the new USDAA heights (although I am planning to keep him in 16" performance).