I look at it this way based on what little I know about strings and physics. Your string length has nodes at all the many harmonics for the note it is tuned to. The string length changes as you fret the neck and play. Therefore all those node positions change too as you play. Put a pickup anywhere and it'll be better for some note but maybe not another. A pickup placed near the neck will pick up a wider swing of the string as opposed to the bridge where it is anchored.... My conclusion....put the pickup between the neck and the bridge.