I found this bit of info for the scoring.
Round: 100 points
Square: 1,000 points
Diamond: 5,000 points
Triangle: 10,000 points
The special hidden targets are worth even more, i'm not sure on the exact point value of those hidden dots. My mistake the first few times was that i thought that when a target was flashing you couldn't get points from it and i was wrong. If you find a triangle just keep shooting and try to hit it 4 or 5 times in a row which will increase your score.
I'll be going to

on the 12th of this month hopefully the park will be fairly empty. I went for bats day recently and the place was pretty crowded.