This is how ours turned out:
The rail ended up as at 10 feet, I know short but I have no experiance with rails at all. Atleast since Febuary when I was competing in slopestyle I tried to through a rail into my run... Landed on my gut and knocked the wind out of me. So I have already fell on it 2 times pretty harsh. The rail is about 16 inches off the ground slightly higher than the lip. It took us 3 days to build. If you check my profile you can see all the steps we took. Heres my friend Patrick Foster AKA P-fo hitting our rail:
We got this thing perfect there are no flaws except later on we will need a rail around 5ft longer and some of that orange construction fence!