All the pick ups are, are magnets that create a field for picking up strong vibrations.
Right over the field, stronger, slightly off the field. Weaker.
Possibly less important with fat pole pieces, if it’s 2 per string, well so long as all strings are dead on or dead off it doesn’t matter, you can equalise loudness of the note with location, height, technique etc. Blades as mentioned, not an issue
so far as narrowing the spacing, it really is not an issue. I modded a Jazz bass to have Rickenbacker pick ups instead. The normal Rick neck pick up is slightly smaller as it is normally closer to the neck heel, and I have moved it backwards so the E and G strings were just outside. schaller 3D bridge brought them all into the field.
Ultimately you’ll do what’s right, but there are many ways to skin a cat, but doing it yourself gives a very customised bass which is sometimes more satisfying