I'd take a really good look at the one T you had where the relationship was "transformative". Try to figure out what worked in that relationship. How did you feel at your very first appt? Did your gut tell you that this was the one, or were they just OK at the beginning and then the relationship deepened. What kind of a personality did they have? What was their therapeutic focus?

I'm just thinking that if you can identify what was so good about that T, maybe it will help you find those traits again in the ones you interview.

And I think googling and interviewing by phone is a great way to whittle down the candidates....good luck!