Started with 1.8 mm (US6 steel hook), but that was too small. Moving up to a USB/2.25 mm hook!

Moving the thumb gusset to the other side of the hand - this requires finishing the wrist after round 1 then doing the gusset across from the beginning of the round. To get the shell between thumb and palm, make a shell through both sc4 and sc6 at the same time. Skipping the extra rows on the thumb, as written is too big and taking out one shell is too small, so it’s fine as-is.