For simple pulling, I would recommend the Gentle Leader - it can be adjusted to fit better than the Halti, and simply it focuses the pivotal balance on the dog's head - whereas if he lunges or pulls with a harness or Halti, all you do is physically pull him to a halt... with the GL the pivot is on his head, so you can avert all the sniffing, lunging etc, simply by pulling across your body, and you have control of the dog without being hard on their neck or body ... It is especially good for dogs who seem careless of their upper vertebrae !!!
They all resent something physical on their faces at first, but this is much better than them dragging at a collar, or being pulled around on a harness... You can still use your collar and lead, and have the GL lead in your other hand so that you can simply correct them gently if they are being silly ...
There is no way a Cocker should be pulling someone off their feet - no-one wants to crush their natural exuberance, but they need to know that this is a way that they get to do their favourite things, so perseverance is required!!
Bramble is 3 in October and still witters and leaps around and generally is silly when he knows he is going out .. he does know how much we tolerate, however, and you need to do that sort of thing in the same way that you taught themn when to get off the settee etc!