For one thing a 44 tooth sprocket on a 20" wheel is going to have a lot of torque but no top end at all. You'll probably top out at around 20 mph wide open. You need a 36 or even smaller on a 20" wheel.
Now I'm not 100% on this but, a 36 spoke wheel has 18 spokes per side and half of 18 is 9 and the sprockets come with 9 holes.
So following that a 28 spoke wheel divided by half is 14, half that again and you get 7. So I'm thinking you need a 7 hole sprocket or you may want to go with a hub adapter.