CB Range discussion

Hi everyone, I’m new to the site and getting ready to purchase my first chastity belt. Could someone offer some guidance? Measuring has been tricky for me, but based on what I’ve done so far, mine is around 8.5cm when flaccid (allowing a margin of error of +/-0.5cm). I’m unsure whether the CB6000 will work or if I should stick with the CC6000S instead. Any advice would be much appreciated!