To make these socks fit a larger foot, just add repeats before working the heel. You will need more yarn for a larger sock! If you want the sock tighter, just increase less for the toe. The pattern repeat is over 6 stitches, so any number divisible by 6 would work.

The socks are super cushy due to the floats of yarn on the inside. They can be worn in shoes, if you like, but are meant for slipper socks and have a bit of a looser fit than I would make socks that go in shoes.