It does help, thank you!
They're almost done, one more thumb ribbing to go. Unfortunately I had to increase for the thumb gusset with yarn B, as it would have taken ages for A to reach beginning o.t.r. marker, because A and B overlapped in the gusset. Wish I knew a way to avoid that, e.g. to start 36 stitches before the increases begin. Or is that a silly thought?