There will be two golden circles at Wembley, on a first come, first serve basis.
The circles are on a first come first served basis, being that the first people down to the front of the standing area will get into them. That means not necessarily the first people in line will be guaranteed a place but they will stand a good chance of getting there. Apparently the circles are similar to the ones at the George Michael gigs last weekend and a similar size. People in the circles will be given wristbands, so they can enter and leave whenever they want. It is NOT a one in one out system.
As for the different entrances, they enter the pitch at roughly the same place, so everyone will have an equal chance of getting to the front.