I'm in Michigan too. I personally recommend the Z-Spray units. That many customers and that size lawns tells me you could use a Z-Max but I get the logistics issues of stowing a trailer or trailers.
They have a new rackable unit that you can put on the carrier rack and haul with your pickups that they just came out with.
Honestly though I wouldn't do the kind of lawns you do with anything but a Z-Max. I use mine on lawns from 4000 sq feet to 1.3 million sq feet.