In hindsight, I might not have used Bondo. Not if there's something that actually dries more slowly. I wasted twice as much filler as I used because it dried up before I could apply it. You'll have seriously less than 5 minutes with Bondo. It does work well, mind you, if you can manage to work quickly or can afford lots of it.
Heads-up: the label says that this stuff causes cancer if the fumes while hardening are inhaled, or the dust while sanding.