Hi-just wondering-do diamond prices go up or down at certain times of the year-for example around valentines day?is there a best month to shop for diamonds? and my current diamond has a large culet and it is basically sitting on the setting with no hole behind or any light in that area-would the visual yuckyness of the black spot of the culet look better if i raised it off the setting or drilled a hole underneath the diamond through the setting? thank you