The eccentric hub should nominally set the axle between the 4 and 5 o'clock position (viewed from the left side). But you can also obtain the proper chain tension when the eccentric is in the wrong position - with the axle set between the 1 and 2 o'clock position. If it is set higher than the 3 o'clock midpoint, there will be inadequate clearance between the lower run of the chain and the swingarm and the rear ride height will be too low. You'll also have inadequate clearance between your rear tire and hugger clearance so it'll rub.