I use the Liuxin Newman method--no need to develop callouses on any fingers at all.
She also sells silicon fingers to put on the index finger to help pull the needle through. What I like about them is that there's a little patch you cut out of them where your fingernail is, which helps prevent them from feeling sweaty.
I seem to be plateau'd at 8 stitches per inch but I haven't had much time to practise--too busy reading and learning!