I say, and with God's help: It suffices if the fingertips are overlapping, so that water flows from his fingers to their tips, and if he extends them, it is as if he has taken new water, and the amount that gets wet from the shoe upon placing it is the prescribed amount — the length and width of three fingers of the hand. However, if the fingertips are not overlapping, it is not permissible; because the wetness becomes used as soon as it touches, and if it is not overlapping, the previously used wetness becomes used again in the requirement. See: Al-Muhit p. 340, Ghunya Al-Mustamli p. 110, and Sharh Al-Wiqaya p. 114, and God knows best.