sept 10 - just before you arrive they will be running hard...then again the 28th til when you get back.
Plan to spend some time between the 15th and when you leave. I'm averaging about 40 hours per 40"+ drum, some say 100 hours is good...gotta put the time in, with good conditions of course!
Fish hard for 3 days and your odds increase greatly IMO, otherwise your just casting a prayer out there. I really hope you get one.