It sounds like you are already making progress, realizing you have a different dog is the biggest step.
Force fetch and the e collar are just tools. When used properly they make for better trained dogs and happier trainers. Many ascribe an age requirement for deciding when a dog is ready for FF. My wife and I have found that doing based on a dogs development/behavior works much better. When a dog starts to make decisions about whether or not in needs to obey a command is the right time to start FF. Force fetch is not about retrieving. It is the first step in teaching a dog that obeying a command, inspite of 'pressure', is the only option. I have done FF on dogs prior to them getting their adult teeth. I have found to it to be easier and usually faster with a younger dog.
Since you want to train your own dog I would encourage you to find someone to help you do FF with your own dog. One very important benefit is seeing how your dog responds to the pressure/ear pinch. You are likely to see similar behavior later on in training.
The easiest problem to fix is the oe you don't create/allow to develop.
Have fun with your dog,