From: Rabbi Moshe Sofer
To: Rabbi Shlomo Segal
The Chasam Sofer validates the proposal to send the appointing witnesses together with the agent to circumvent Rabbeinu Peretz's restriction on shaliach kabbalah, but identifies a separate problem: the wife's appointment must occur during the husband's verified lucid period, and if his lucidity follows no regular pattern, combining two witness groups raises an unresolved chatzi davar problem. He declines to rule leniently in a matter as severe as eishes ish.
Source: Shu"t Chasam Sofer EH II §42