From the high level view the first half of the marathon - it very much looks like the Bristol Half Marathon route! which I've ran lots of times. Very flat, wide and fast. Starting @Bristol along Hotwells Road - up and over the Cumberland Basin head out a couple of miles on the Portway till you get to the first major junction turn and run back under and up on the Cumberland Basin onto Cumberland Road which runs along the "Cut" river Avon in Southville into Queens Square etc. etc.
No probs. That's landing on the front of your foot and not your heels. It took me a couple of months to adapt and it come naturally. You don't land on your toes, You try and land on the ball of your foot (the padded bits where your toes join the foot)
I agree with Ben. Not worth using in a running shoe. I do use them in my 5 aside football trainers as it can be quite jarring. Better to look at your running technique. Since I moved to fore foot running 4 years ago. I haven't had shin splints and follow training plans to avoid over training.