Consider a Bluetooth selfie button, so you don't even touch the camera once you get it positioned on the stack of whatever. As for the stack, I happen to like a block of wood, cut to the exact right size on the table saw. You can cut blocks for each coin type and never have to mess with finding "the" book.
The Denver Mint produces a nearly prooflike finish on many Kennedy halves. I have several actually certified as prooflike, because the look is on both sides. Frequently, the reverse holds it back from qualifying. The Philly Mint produces a far more "frosty" finish. That said, I have found NGC MS67 examples of each mint. They look nothing like each other, but they're both pretty darned nice in their own way. If you search a 200 coin bag of Kennedy halves, you should find maybe 3-5 MS67ish Philly coins, and maybe 6-10 Denvers.
very nice halfs i have been getting rolls of half dollars from the mint for alot of years never opened any of them sometimes i wonder if there are some extra good ones but i still will not open them welcome back into the hobby
Up until 2014 (flatter relief) your rolls will likely contain some real nice ones. Starting in 2015 (higher relief) they have a tendency to show coin on coin rub on the obverse high points.