The first time I installed the o-ring, I did it from the top. It was hard for me to check the movement of the pick up tube.
The last time I did it, I did it from the bottom. I dropped the oil pan, and removed the 2 bolts that hold the pick up assembly. I slid the new red o-ring over the snout of the pick up tube and slid it down to the base of the pick up tube. I tightened the bolt down and the metal retainer got sucked up into the oil pump. There was no up/down movement on the pick up tube.
That is how I did it. The problem from doing it from the top is that the 2 bolts holding the pick up assembly to the engine maki it hard to feel for movement on the pick up tube. When I get home today, I will snap some pics of the o-rings to show the differences.