[buying a grandfathered full sim.]

If I wanted to buy a grandfathered full sim, would I also have to own one full prim sim?

[how do you fix the gap between slink feet and your leg?]

How do you fix the gap bettwen slink feet and your leg.  I have tried different size slink feet, I have tried adjusting the length of my legs, I have tried ankle blenders, I have tried my avatar skin blender, I tried to change the feet (can't), and nothing seems to work.  anyone got an answer for me?