Hey Dave, welcome to the forum!
A lot depends on whether your tuners allow you to simply ADD channels, VS doing a complete rescan. After you do a scan on some tuners, a second scan wipes out the first channels scanned.
Rotors are time consuming and prone to failure.
You can combine two antennae into the preamp, or you can use two antennae and two preamps joined w/ an A-B switch.
The last option is what I do, but you may not care to shell out for an additional preamp.
At your location, you may even be able to P/U Michigan w/ a rotor.
I like this website too, cause it shows stations that don't show up in TVF.
http://www.antennapoint.com/antennas...+Search&search[uhf_ant]=1&search[vhf_ant]=1&search[min_erp]=0&search[max_erp]=9000&search[max_distance]=150
Good luck and GO PACK!