What does asymmetrical winding of bobbins in a humbucker do?

[Crossfire]

So I'm experimenting a little bit.

What in theory would happen if I overwound one bobbin in a humbucker by like 500 winds relative to the other bobbin? Does it impart any character, or does it just start to become noisy?

[Helmholtz]

Gibson has been doing this for many years with their Burstbuckers.

The coil with more turns will be more sensitive than the other one.

This might add a little single coil treble particularly on bass strings (main purpose).
It also acts as if the PU position/center was shifted a bit towards the stronger coil.

The unbalanced coils will somewhat reduce hum-cancelling.

[Antigua]

The funny thing is that in series, the coil with more turns is of higher output, but in parallel, the coil with fewer turns has lower output, because the coils act as mutual loads, and the coils with fewer turns sees less of a load than the coil with more turns of wire.

[big_teee]

I like symmetrical on the neck, and asymmetrical on the bridge.
On the bridge with more turns on the slug bobbin.
You will need to experiment to see what you like.
T