Just went through this whole thing myself, Chad.
Personally I think the best thing to do is demo at the hill itself. Not sure about the other contenders mid-state, but up North you have Boyne Mtn. or Nubs, not sure about the Highlands. At Boyne I know they have Head, K2, Atomic, and I think Rossignal, maybe Nordica. You've got the link for Nubs.
Boyne will put the $50 against any ski purchase at Boyne Country Sports; not sure if you have any on your side of the state. Nubs has an arrangement with various ski shops around the state, where they will give you some kind of voucher with the demo amount ($45) on it; the pariticipating shops will then basically discount the ski purchase by that amount. If you have a local favorite ski shop you can ask them if they participate with Nubs demo program; they will know what you are talking about even if they don't participate. You can also call the Nubs shops and ask them if they have any GR shops on the list; they keep it handy and get asked this question all the time.
Both demo shops are right at the base of the main slopes and are very easy to access, and both had good personal, and quick change-outs of skis so you can demo as many as you want or as is practical.
Hope that helps.