Chastity and orgasm denial discussion

This is my very first experience with chastity play. As you can see, I am using a metal cage (made in China). I bought it with a 50mm A ring because I figured it would fit me best. Actually it is too big. So I tried to put a smaller (43 mm) ring in front but this hurts very much at night (can’t stand it). I am now wrapping a pantyhose around the ring so it gets smaller and also slips less. This works quite well. I am planning to purchase a 45mm ring next time. Now my “bigger” problem is the size of the cage itself. My glans is quite big and even when fully flaccid it is extremely difficult to fit my penis into the 35mm cage. I have to kinda “screw” the cage onto my penis but I figure this could hurt my piece of meat in the long run. Any suggestions?