I BELIEVE the best places(yes two!) to put the pressure taps are as close to the wear ring that you can on the top (right up next to the hand hole 10 or 2 o'clock) and the bottom as close to the bottom as you can (the 5 or 7 o'clock position). This is because the shoe controls most of the bottom load and the loader grate controls the top load. These two pressures are quite independant of each other and should be roughly equal. Having only one tap in the middle (3 o'clock) only reads the average of the load and can't discern top from bottom.