Actually, Wisconsin law (ATCP134.09) says he is only required to give you 12 hours of notice before showing the property, so if he's giving 24, you won't get much legal wiggle room to beef about on that point.
See http://www.legis.state.wi.us/rsb/code/atcp/atcp134.pdf
It's your home, but it's his property, and unfortunately, he does have the right to show it aggressively until he finds a suitable buyer or tenant, so long as he's not violating any standing statute or ordinance.
See also Wisconsin Tenant's Rights
Personally, if it were me, I'd be moving that kitchen table OUT of there on days when he wants to show the place. He gets to show the unit with proper notice, but nothing says you have to also provide accomodations for him to sit down and do paperwork.

