I set the time for my editor to do her thing several months ahead. She had some health issues, and reduced her client list - I feel lucky to have been kept on.
Over time, we've learned to work together well - our process has evolved into something that might be slightly unique. She never sees my work until it's complete and I've gone through it 10 to 15 times, looking for plot holes, character development, description, all that stuff - and of course grammar. She uses color codes that indicate the type of work I need to do, and notes about how I could make it better. I then make more passes as we fire excerpts, comments, and questions back and forth via email (she lives on the east coast) until IMO it's as good as it will get, then I self publish.
A little weird, I guess - but it works for us.