Mall arrival time for insiders weekend with GWPs

Our closet Lego store is about 1 ½ hours away. Both the mall and Lego store open at 10 am. I thought some malls open there doors a bit earlier just for people to walk around. How early do y'all usually get there to get a good spot in line. And if by chance there's a bunch of people before us, how quickly do stores run out of GWPs. We never went to a store for a GWP at least so we wanna make sure the 90 min trip is successful.