In training, I never help a dog find a gun. I come out of the holding blind walking slowly to the line, giving the dog time to pick out the guns. I may stop, turn and face a gun if the dog isn't finding it.
Even if the dog has not picked out a gun, I will often have the gun shoot and throw anyway. The surprise of the shot and throw from a gun the dog hasn't picked out will encourage him to look harder next time, teaching the dog to anticipate the possibility of more gunners.
For a dog having trouble looking past a short gun I might ask for some movement from the long gunner.
Even if the dog has not picked out a gun, I will often have the gun shoot and throw anyway. The surprise of the shot and throw from a gun the dog hasn't picked out will encourage him to look harder next time, teaching the dog to anticipate the possibility of more gunners.
For a dog having trouble looking past a short gun I might ask for some movement from the long gunner.