Just looked at it briefly â€“ I think the only thing I find is that I'd like to see the set*() methods to be public. It would allow people to re-configure the object at runtime after it has been setup the first time.
Use-case: query members from multiple lists, or run unsubscribe for one email on multiple lists (e.g. "subscribe me from all").
Otherwise, looks good to me. I don't remember what other feedback there was the last time. Maybe incorporate that in the description of the proposal.