The shop at which I work has a 7 day saddle return policy. As long as the saddle hasn't been crashed or otherwise seen undue wear n' tear, we allow customers to exchange for a different saddle if they bring it back in a week. I think Wallbike has a pretty stellar return policy on Brooks stuff, too. Otherwise, kylejack's method seems like it'd work, assuming your friends aren't too much taller/shorter than you.