How many copies could a first time author expect to sell?There are so many variables that effect sales...you can "expect" whatever you want but that doesn't mean it's going to happen. If you are with DB or Covenant, with good access to the LDS market, your expected sales numbers are going to be higher than if you're with a smaller publisher who may or may not be able to get you into the DB or Seagull stores/websites. It also depends on whether you're writing fiction or nonfiction.
When we take on a new fiction author, we aim for their first book to sell around 2,000 copies. That's our break-even mark.
What is the "magic number" of copies that makes a book a best seller in the LDS market?Best seller is open to interpretation. There really isn't an industry-defined standard. Some companies figure they have a best seller if they go into a second printing. In my opinion (and I've been told by colleagues that my numbers are both too high and too low), for fiction in the LDS market only (not titles that are intended for a national market), I wouldn't award that label until sales went over 10,000; at 40,000+ I'd be dancing in the streets.