It’s hard to say because it depends on the interacting element. I don’t think lock speed is a linear equation, so I dunno about that.
As for other things, let me give you an example. When your weapon sig is smaller than the target sig, increasing the size of the target has no effect UNLESS the target exceeds the velocity/radial, at which point excess size helps to mitigate that.
In a practical example, going from 115 to 125 would have no effect on small weapons, maybe an 8-10% increase vs medium weapons, and potentially no effect(or incredibly small) vs large weapons depending on your velocity.