I used the technique in TechKnitting for casting on the fingers TechKnitting, finishing them with a sewn bindoff.

My father had an accident and lost some fingers on his left hand so standard glove fingers don’t fit. He needs a standard thumb and little finger plus a single larger finger for his middle/ring/index finger area. For that, I cast on 16 stitches using Judy’s Magic cast on, increased as if making a pair to toe up socks to 40 stitches, then joined it using the same technique as the other fingers.

The ribbing is a twisted rib -- only because that looks better than my standard k1/p1 rib.