I've got plenty of experience with tints in Ohio. Legal limit is 50% for the front driver and passenger window. No limit at all for any rear windows - you could paint them if you really wanted to. And the front window I'm pretty sure is 50%, but more importantly you cannot tint below "the line"... if you look at your windshield about 4 inches or so down from the top, you'll see a small arrow and a line... can't go past that.
What I've found is that it really depends on your local PD. When I lived in Cincy in high school I had an 'ol beater red mustang with 35% front and rear - don't ever recall getting pulled over or ticketed for it. More recently in Columbus, I had a dark grey Cherokee with 20% front, rear, and a pretty low strip on the windshield.... and also had a very light grey Intrepid that had a black roof and 20% front and rear - this one "looked" very very dark just because of how the car was setup. And the Intrepid is the only car I remember getting a window tint ticket in.
But that has a long story behind it - short version: I was drinking an IBC root beer and cop thought I was drinking a beer. He pulled me over and was an a-hole, so I went off on him. Since I obviously wasn't drinking and driving, I was rewarded with a window tint ticket. It certainly wasn't the reason why I was pulled over - but it was his only option to hit me with something.
Most recently on my 300, I have 16% front and back. Yes, 16%. Well, I paid for 20% but according to Columbus PD it is 16%. So yeah, I got pulled over in my 300 not even a week or so after getting my tints. No ticket. Actually a nice cop who had an old Cuda and apparently our shared love of Mopar saved the day.
But here's what he told me: CPD doesn't care about window tint tickets and will rarely write one, unless they are simply choosing to be a-holes. However, they will use the window tints as a reason to pull you over and make sure you're not a "bad guy". So it's basically an open invitation to be pulled over at anytime, but unlikely to get a ticket. I've seen that cop many times since and even get a wave out of him sometimes - never been pulled over by him since. Nor any other CPD (well, for the specific reason of window tints at least
He also told me that State Highway Patrol and Sheriff's love to write window tint tickets. Again, I haven't been pulled over by them either for window tints, but this cop's warning was more of a: "us city cops have bigger things to worry about, but the rural cops love to nit pick". Knowing you're in amish country, it is really going to depend on how the enforcement is there. You know what I would do? Just ask a local cop. And keep your eye out for tinted windows at gas stations and parking lots you are at, and ask them if they get harassed by the local PD.
As far as state law vs local law, I've never heard of a local law being enforced over the statewide 50% law. Pretty sure that is the standard for all of us in OH.
And as far as the tint, you'll probably have an option the jumps from 50% to 35% to 20% to darker. As said earlier 50% is worthless, unless you are committed to staying legal. But 35% will look good and not draw too much attention. 20% is when you start getting pretty dark and it's clearly noticeable. But remember it also "looks" different depending not only on your car color, but sometimes even more specifically due to the interior car color.
One last thing I must say - forget any "deal" you see on window tints. Make sure you go to a reputable shop that uses good products. There is nothing worse than a bad tint job or crappy film. You'll always regret saving a few bucks on a deal. Ask me how I know.
I can recommend an excellent tint place here in Columbus if you are interested - supposedly #1 tinter in Ohio (even though it's a tiny shop). They charge a bit more but worth every penny.
And that's what I gotta say about that!
Hope this helps!