You mention the number of holes exposed on the L brackets, but that really has no bearing. Starting out, its best to have the bars are even. This will allow quick adjustments on the road, up or down.
And if you adjust the L brackets up or down, you may find it best to change the angle of the head & bars to again bring the bars level. The steel on steel friction of the bars on the L brackets are the built in anti-sway. The more flat surface area meshing with another flat surface, the better. You don't want the bars at too much of an angle, and rubbing on just an edge of the L brackets.
