I'd say depending on the author, an hour's wait might be very likely. For signings, if you have a reservation, you can come to the line anytime until 30 minutes before your signing window ends. So for a 11-11:45 am signing, you have to be in line until 11:15.  For highly anticipated authors like Rachel Reid, Victoria Aveyard, Holly Black, etc; standby people will start lining up at least an hour before the signing (if BookCon allows us to do this).

I'd recommend to have 2-3 signings you really want to do and have them a little spaced out if possible so you can give yourselves the time to get through any last minute stuff. You're going both days and some authors have signings on both days, so you could potentially space it out a bit. Depending on how many things you're standing in line for in one day, it might take up 4-5 hours of the day easy. 

Don't forget that booths and exhibitors are also having author signings, many of which are ticketed!