I always struggle with the tiny small vertical "A-Z scale" on the rigt side of the screen of my iPad.

It is hard to target and get the right character on first try because it is way to small for my finger tip.

I suggest to switch to an mouse-over effect for this section to see clearly the touched area or to increase the width of the scale in general (maybe offer small/medium/large size)

That would be really convenient to smoothen the useabilty even more :-)