CB6000 Compared To Size Issues

I just purchased myself a CB6000. Unfortunately, with this type of product you can’t go and test it in the fitting room, so I bought it without trying first. Now I am dealing with sizing issues. I have somewhat substantial girth, so I used the largest ring from the set. Even that ring feels kind of tight, but it resembles a snug cockring, so it is not too much of an issue. However, the cage itself is small. It took about 5 minutes in a cold shower for me to shrink enough to fit inside. Once it was on, my skin was pressed between the cage and my scrotum, pushing out through the “ventilation” holes at the base. I wore the chastity device for 4 hours and found it comfortable (or at least no worse than expected from a typical chastity cage), but when my penis tried to become erect, significant pressure was placed on the pins. I doubt they will hold up well like this. I am also thinking about wearing it around-the-clock. Because the holes are blocked, there is poor ventilation and washing inside becomes difficult. So I wonder about hygiene and cleanliness. Does anyone here have experience with this? Is there a larger cage option for the CB6000? Or did I pick the wrong device and should I look for a bigger (plastic) one?