The best concrete pads are at the old zilker park in Austin. They are pie shape, kinda. I think 4 ft. in front and about 12-15 in back and 10 or 12 long.
I actually thought as far as cost was concerned - Zilker Park used too much concrete. I only used about a third of the tee when I threw, and the rest felt like wasted space. And again, how much more are spending in concrete. Flip City is a good general design for how the actual pad should look and Circle C Metro Park @ Slaughter Creek is a great example of what the area around the pad should look like.