No, I had a helper. The left and right centering stays the same, the arc of the boom lowering is what I have to account for so I divided the length of arc I need by 2 and started on the high side of the arc so the forward and aft movement was minimal. What helped here is the weight of the cam was fully supported and lowered at an ultra slow speed, allowing my helper to guide it through the bearings at a snail's pace.