What I have found is that if I don't click on the notifications then after two notices I don't get any more. So you may want to click on the notifications to go to the thread each time so that the system knows that you're still interested. On most other websites were I have email notification it continues to send whether I still want the notices months later or not, lol....but disboards seems to be considerate and stop them if you don't show some interest after a couple.
I was able to get my first choice date for November and am hoping to snag one for December as well, so I've been clicking every notice that comes in, lol.