When you're picking an instructor remotely, anyone credible is going to be willing to spend time on the phone or on Skype with you. Cave diver training is a serious commitment that goes both ways - they also want to know that they're a good match for you and your needs before you start dropping $300-400/day on training. You'll have time to ask about their training methods, philosophies, preferences, etc. You can also ask them to provide references from previous students and make separate calls.
Gold.