Sorry, got distracted by insomniac DD!
You can express an interest with as many rescues as you like. In fact, not only is it a good thing for you, giving you more chance of finding the perfect dog, rescue would prefer that you kept an open mind and your options open than insisted that you wanted Rover even if they felt he wasn't quite right for you.
With all rescues, ensure that you accept no less than this:
One which homechecks - this is for YOUR sake as well as the dog, they want to ensure that they can iron out potential problems before they become an issue and find you the perfect dog.
Which neuters, vaccinates and chips as standard.
Which offers lifetime support.
Which insists by contract that the dog will return to them if ever you can't keep him, even in 10 years time. Heaven forbid that this should happen but if it did you would struggle like feck to find a rescue place for an unwanted Sighthound - even I do and this is what I have been doing for years and I have country-wide contacts.
One which assesses its dogs thoroughly. Don't stress that the dog has come from racing kennels or a pound and not a home, that's not a problem. What you need to know is that the rescue has worked with him and can tell you what his prey drive is like, what his recall is like, whether he's suited to a family life and so on, whether he's housetrained or not.
Remember that some Sighthounds aren't housetrained having lived a life so far in kennels, but that is far from an insurmountable problem, it just depends on whether you are willing and able to train him. I would - I have solid floors and older DC but if you have, say, carpets and a crawling babe you may like to consider one of the many dogs which are housetrained.