Have you tried how much space you have when you put all of your charm on the 23 cm bracelet? That's currently the most 'empty' bracelet, right? Also an idea is to link the two bracelets to each other and wrap them around your wrist twice. Maybe that's a fun way to get the right length.
I do like how colorfull your bracelets are! Large pictures are better than fussy pics, doesn't matter.