As my tab wore in, the orginal rubber finger divider started to let go of the leather.  I quickly designed this replacement with a slightly larger retaining area to keep the leather bound together.

I printed mine from ASA, but I want to try TPU next.  With a soft tab (original is rubber/soft plastic) it bends with your fingers.  With a hard plastic it doesn't.  It's not uncomfortable but it's different and takes a while to get used to.