Anything you do, including doing nothing, wrt to pickups, string gauges, action heights, neck relief, bridge/saddle types and materials, fret material, break-angles, fret dispositions (fanned frets, if you like fans) compensated nuts and string height above body will get you an argument or discussion or death threat on most of the gear head/technocrat forums.
Move a pick-up away from the bridge it gets warmer/sweeter for obvious reasons for any given note/chord. From a harmonic point of view it's a more complex situation as the harmonic is still tied to the fundamental and subsequent string and guitar body/hardware induced harmonics , or pinch distance for pinch harmonics, and given the relative frequency wavelength compared to the magnetic aperture I can't really see that it matters much (or as much as it is held).
But, I must go and rearrange my sock drawer as it hold a better prospect of a meaningful outcome than to try and figure this one out.
I know location makes a difference , and neck pickups are often at 2nd octave node , but to me its crazy because that 2nd octave is only relevent to open stings , if youre playing in C or F or whatever the pickup is no longer in the sweet spot to my mind . Please inform me of my ignorance !
I find that the tone the pickup delivers is directly relateable to the tone the unamplified string delivers when plucked/picked at that location. It's going to change every time the string length changes as the string is fretted to different notes so it's always a compromise , but for much of the fretboard it's going to be affected more by the distance from the bridge than the distance from the fret. In all honesty, I think that the length of the fretboard decides the location of the neck pickup and the clunkyness of the bridge decides the location of the bridge pickup as much as any other factor. I know that Les Paul had guitars where he could locate a pickup anywhere from the neck to the bridge and did many experiments - I would be surprised if his knowledge did not inform the design and pickup placement of the classic Les Paul guitar, which in turn informed all similar guitars to some extent. I expect that the Telecaster and Stratocaster pickup locations, for the bridge anyway, were likewise subject to some experimentation. But not mathematical node analysis - just what sounded good.