Trouble with Chastity Cage Fit and Wear

So, as promised in the “Hello World” thread, this is my question/problem regarding my chastity cages. Currently I own three cages:

• a metal one
• a CB6ks knock-off
• and the holy trainer I am able to wear all of them during the day without any problems. But when wearing the metal one at night my balls turn purplish and my stomach starts to ache. I concluded that the base ring was to small (4,5cm/1,77in) and since it is only shipped with one ring I am not able to wear it at night. Although it appears that the cage is a bit to long. I am able to wear both the cb6ks knock-off and the holy trainer at night without pain and with the holy trainer I’m using a 3,6cm/1,42in ring, but due to its form it doesn’t cause any problems. I’m using 4,8cm/1,89in with the cb6ks and I’d like to try smaller ones, but I seem to have misplaced them. That being said I prefer the holy trainer, because it’s rounded edges are more comfortable to wear at night. However, when wearing both of these cages my penis seems to be able to slip out during the night. The erection starts and the base and applies constant pressure to the cage and penis. After a while or after several attempts my penis slips out more and more, until finally it forms some kind of arc and only the head remains inside the cage. Once, the head slipped out too and another time I pulled it out half-awake. I can sort of alleviate this problem by inserting my cock with the sock method instead of pulling my foreskin back when putting it into the device, but I am only able to wear the cage for an additional day. Furthermore, my foreskin starts to swell up and although it does not really hurt, it doesn’t seem healthy either. When my foreskin is pulled back my penis has more space to grow during the night and is able to slip out more easily. Do you guys know how to solve this problem? Theoretically I’d be willing to buy a different cage in the not to distant future, but I am at a loss concerning what causes the problem to begin with. Right now, I am able to wear the two cages for about 2 days, but afterwards my cock has either slipped out and sometimes my foreskin is swollen as well. But my gf would like to keep me locked up longer than 2 days… These are my personal “specs”:
• flaccid penis length: 10cm/3,94in
• erect penis length: 17cm/6,69in (I know that the base circumference is important as well, but as mentioned above I am able to comfortable wear a 3,6cm/1,42in ring, which is the smallest, with my holy trainer, but the 4,5cm/1,77in round ring restricts the blood flow)

It sounds to me you have either a gap or cage diameter problem. To give a good response I thing one more piece of information is needed. What is the diameter of your flaccid penis? The cage should be almost the same diameter as when you are flaccid. This is so when you start to erect the cage grips you and doesn't allow movement. Then when you go soft again the cage is in the same relative position.