The little finger sticking up so you cannot use it can be caused by having the whole hand in the wrong position.
The neck will be in the way, of course, but the thumb ought to be in such a position that it can fully oppose all four fingers. Try it without the neck in the way first. Make a ball shape with the whole hand and touch the tip of the thumb and the tip of each finger. The thumb needs to be cocked. Try it again wihtout the thumb cocked and you can't do the oppositions properly, especially the little finger. Once the neck is in the way, make sure you are cocking the thumb into the opposable position and then all four fingers ought to come into play.
Works for me, might not work for you.