I know your new here, So im going to help you out a little bit.
First of all, Sunday usually is the best day but the crowds for fright fest are always heavy, unless theres rain which really a cold rain would suck anyway.
Best bet is always Fright Fest Friday's. those are the 3 Friday Nights in October where the crowds are usually lighter then other fright fest nights.
Secondly, please before posting do a topic search, especially for trip reports to give you the best ideas for how the crowds are going to be.
It is impossible for use to just guess what crowds may or may not be in the future.
Here's one thread to start with.
http://www.sfgamworld.com/phpBB2/viewtopic.php?t=7987&postdays=0&postorder=asc&start=0