What is the sufficient amount to wipe on the khuffayn, and is it sufficient to wipe with only the fingers, or must the palm of the hand be used, and is it a condition to take new water for wiping, or is the remaining water from wiping the head sufficient?

Any method of wiping over the khuffs is sufficient, but the best way is for the person wiping to pass their hand from the tips of the toes up to the shin only. The wiping should be done with both hands simultaneously on both feet; so, the right hand wipes the right foot, and the left hand wipes the left foot.