I know the subject of the correct time to wait for a reply from a provider has been covered a zillion times, but I just have to add another thread.  

I contacted a provider in early January to ask if we could meet. She did a check on me, then gave me some dates. I initially said the 15th of February, but then realized I had something going, and asked about the 22nd. She was going out of town, and wouldn't be back until the end of the month. I asked if I should contact her then, and she said that would be good.

Saturday night I emailed her to ask if she was back in town, and asked her to get back to me. I waited until Wednesday, then emailed her again, asking if she was back to her regular routine. She replied back, saying she was back in town, had a great time, and hoped that everything was fine with me. No mention of us getting back together.

I emailed her back immediately and asked if we could meet. I said any time was good, but I prefer weekends. No reply as of yet.

I'd really like to see her, but there's another provider I'd like to see as well. That provider is very low volume. She travels a lot on business, and is all over the country, and will set up meetings in cities when she has the time. She's going to be in a city a few hours from me at the end of the month. She probably only has a few hours available for that day, so if she gets booked, that's it.

I've really screwed up on protocol before, which is why I'm asking about this here. How much time should I allow for the first provider to reply? If she doesn't reply by tomorrow, I would assume I've given her ample time. Yes? If I book with the travelling provider, and the first replies, should I just tell the truth and say that I booked with another?

I know this sounds simple to most here, but I can screw up the most obvious things in this hobby.