Which audio file(s) to use

Hi all,
I'm wondering which audio files to use for myself - apart from the free one - and which ones should be used with clients only?

Can I use the free one -is this also called the basic audio file?- in conjunction with the Positive Audio files or the EEf audio files for myself and or the clients? Do I need to use the basic free audio file at all?

What are the EEF files for and when should they be used?

Just of late, I tried using PSTEC for use in thoughts, rather than negative emotions and physical discomfort and in my case, it worked quite well. I'm not sure if it was luck, or the belief that the Technique could be used on just about anything and everything.

I'm also trying an experiment where there maybe be complete success in the clearing of negative emotions and wondered if one could still clear the already negative emotions again, even if there isn't anything left to clear or tone down?

Also, I find myself somewhat addicted to the sessions in that I really look forward to using them and get a tad annoyed that I can't use them when I'm ready. I think I might have to make an appointment with myself to go to a session.

It's all so exciting and hopefully I'm not doing myself any mental/emotional damage by using PSTEC other than what it was designed to do.....

I'd welcome any help here.

Armand