VERO MONTE6 Pairs Womens Cotton No Show Liner Socks *Silicon Non-Slip Grip*

Im size 71/2 - 8. Should I go smaller or bigger, as the size 8, falls in both sizes?

I wear an 8 in athletic shoes, and a 7 or 7.5 in flats. Not sure which size to order?

Do these socks slip off the heal of your feet when wearing? I hate when the heal slips off and bunches around the middle of my shoe.

Is there something between the middle cut and super low cut ?