Thanks to all for the words of encouragement. I've been agonising over the following step and trying to figure out how to make a proper ring of plastic around the orbit of the ankle and hip ball socket receptacle and the following is how I finally managed to accomplish it.
Surprisingly simplicity itself but the most obvious somehow escapes us. I started by gluing with a good grade of thin liquid plastic glue. I use 'Tamiya - Extra Thin Cement :
I glued the selected piece to the periphery of the socket using the installed ball as an inner guide. fortunately I used wooden spheres so they are not affected by the glue. I imparted a slight curve to the ring strip initially and started a bit before the desired location so the beginning end could be cut off leaving a curved beginning.
Applying pressure with your thumb (or favorite finger) serves two purposes; one it is a clamp you can rely on to make the proper curve and two the heat of your hand speed the drying of the glue.
Following the curve of the ball make gluing every 30 degrees or so being careful to not let the glue flow back to the starting point as it may dissolve the original joint and you'll have to start over.
working your way around the ball to the starting point, cut off the short straight piece from the beginning and cut the end of the strip to butt with the beginning and voila; a perfect ring of plastic.
I needed a second ring to thicken the ring on the ankle and hip but the second layer is easier than the first and my only complaint is why didn't I think of this sooner.
The mentally challenged Blackadder