Accurate bending is all about having a good ear.
Strings have different tensions all over the neck, furthermore different strings have different thickness further complicating the whole equation.
If you want to be accurate at bending try this simple exercise. It's very simple, logical and most of all effective, probably the only exercise I've relied on for bending.
Play your origin note, ie. the lower note you start from, then fret your target note, ie. the note you want to bend up to. Then BEND AWAY! Try your very best to bend up and hit the target pitch. And then familiarise yourself with pitch intervals, ie the distance between 2 notes, half step, whole step, one and half, 2 whole steps, heck maybe even further than that.
Oh yeah, whole step is 2 frets, half is one.
Do this, repeat and apply.
I sincerely feel this approach is much better than the, whole step is this much strength type of approach, just doesn't make sense when you think about it.
Takes a lot of practice but it's hella worth it, it's an extremely important technique to master. To me electric guitar is just not electric guitar without bending, nothing like hitting a screaming bend and shaking it all over the place like there's no tomorrow!
And trust me there's nothing like hearing someone bend out of pitch, especially if you have a sensitive ear. PURE AGONY
Think finger nails on a chalk board.
