I've often reached out to multiple Dommes when traveling on a tight schedule. As long as you do not commit to anyone until you have decided, with certainty, that you will be arriving for a session, I don't see the harm. A lot can be learned in correspondence and how the Domme handles herself while communicating with you. I've always approached this in a manner to respect the Domme's valuable time but also with the priority of obtaining a session that will work for me. For whatever my advise is worth on this, I think your approach is spot on.