Have you tried to use them on MTB or just road? Last winter I used lobster gloves that we're 1+3 with the index finger on its own. Did not like the glove within a glove design and bought a single layer pair like yours ( also 2+2 finger setup ) and found the MTB shifting to be annoying as the middle finger needs to move with the index finger. Likely fine for road however...
works fine with a twist shifter
isn't sram thumb - thumb? i though the new shimano stuff can go both ways too.