Help with helmet sizing !! Korda Sonic GP

My head measure at 58cm, and recommended size is Medium which is a good fit but a bit loose near the cheeks area and helmet shakes a bit too. The small size gives a tighter fit near the cheeks and throughout the head as well. But these were brand new helmets so once they break in, i feel the medium might become too loose.

The actual problem is I am wearing glasses and they simply do not fit in the small size helmet and this helmet does not have the cut out for the glasses. Is there any jugaad i can do to fit my glasses on the small size??

What do I do ?? I really like the Korda Sonic GP or should i switch to different brand ???