I would offer a lot of "it depends" if you were asking about a clean sheet driveway.   But since you ALREADY have sunk investment of an elevator that is standing, wired, operational...    Buy a tank of gasoline.   Get in a car that's full of that gas.   Spend a day driving around looking at how many people have a leg or two standing next to some bins that don't look very big now, and outboard of those bins are conveyors of some sort leading to bigger bins.    You'll only ever have one chance to maximize the real estate that is in the closest proximity to where your downspouts originate.