The day doesn't matter to me as much as the date. Wednesday would probably be my preference, so I can get more runs. But I would be down for Friday to watch the fun cars, too.
You say sneak a cooler in for sodas. Do they sell concessions? I assume alcohol is not permitted? Not for me, but I'll need it in order to convince the wife to join
A couple weeks notice would be ideal for me as well. My schedule tends to fill up last minute, so getting something on the calendar early is best way for me to commit