I am currently looking for an e-collar and looking at either the Sport 50 or 60. The only difference I am aware of is the tone mode on the 60s. I am using my retriever for hunting and like the small transmitter of the sports models versus the large field/pro models. Is there a need for the tone mode or is this just a preference of certain trainers? I am looking for any suggestions since this will be a large expense for me. Thanks for any help!