Chastity and orgasm denial discussion

I placed the order tonight and just need to double-check the sizes. I could use a bit of assistance with the base ring (which is anatomical). I’ve been using a 45mm one, which feels slightly too large for me; however, within a CB6KS device, I can’t go smaller because it pinches and digs in where the pieces meet. The next size down from that would be 42, but what I’ve read suggests going even smaller with anatomical rings. Should I order two made-to-order rings alongside this? Would you recommend getting the 42 paired with a 40, or perhaps a 40 and a 38? Also, regarding tube width: mine is about 30mm, but should I allow some extra room for the insert?

Thanks in advance!