Mature Metal discussion

Hello, I have received my sizing rings and I’ve got a couple of questions. The 1 5/8 fits well enough. It seems the right ring should only let you slide one finger in up to the knuckle. Mine allows two, but just barely! Trying the next size down (1 1/2) was quite a struggle. It was very hard getting my second ball through the ring, and then I couldn’t get it back off! I waited ages for my cock to shrink enough, but without success—I had to melt the plastic to free myself! When using a small ring, do you often need to wait hours before removing it? Is 1 5/8 too large and allowing pullout? Should I purchase the larger ring along with the anti-pullout system? Perhaps there is an intermediate ring size? Another question: what is the difference between the A ring for a cage and a standard cock ring? The advice regarding cock rings says not to wear them for more than 30 minutes, yet cock cages are worn much longer than that. Thanks for any advice.