My general impression is that behaviorists work to correct problems based on each individual dog's personality and current theory about dog behavior,
while
trainers use techniques they have utilized and perfected less interested in individual dog personalities.
This of course in an over-the-top generalization and many utilize mixtures of both approaches.
As far as pulling on the leash, if the Halti collar doesn't work, you might try a Halti no pull harness. This harness has straps that go under the axilla (arm pits) and attach to the leash. If a dog pulls, pressure is put on the axilla and that's uncomfortable to the dog. It tends to give better control than a choke or pronged collar.