What I did was to knit a sample piece of about 20 stitches in stocking stitch for 20 rows. I then measured around my hand, just above the thumb and calculated that I would need 42 stitches to fit quite snugly.
Cast on 42 stitches and work K1,P1 rib for 12 rows. My first attempt was on normal needles and then I stitched the finished work together, but I did not like the result so I worked the next pair on double pointed sock needles.
Work 7 rows stocking stitch. If you are working on sock needles this is basically Knit each row. This takes you to the point where the thumb starts to protrude from the wrist.
Work 6 stitches, move next stitch to a cable needle and leave at back of work, work next stitch, then the stitch from the cable needle. This "twist" strengthens the thumb split. Work to end of row, then work another 7 stitches. This takes you to the centre of the "twist".
Turn work and continue in the opposite direction until you get to the "twist" or "split." Turn work again.
Continue in stocking stitch until the split is long enough to accommodate your thumb.
On the next K(nit) row when you get to the split, move the last stitch to the right of the split onto a cable needle. Work the stitch to the left of the split, then the stitch from the cable needle. continue in rounds until the work reaches the point where your fingers meet your palm.
Work a few rows of K1, P1 rib.
Cast off Knit wise.
Work loose ends into rib portions.
I found that it is easier to make a cardboard template so that I know when the pattern must change. This is far easier than counting rows.
The initial pair which I made were a bit short for my liking, so I now continue in stocking stitch to where I initially cast off, then work a few rows of ribbing. The flittens now reach upto the mid point of my fingers, but can still be pushed down quite easily if I need to expose my fingers.
