Harder to install than to remove
I agree that you should replace the tensioner rail. It is usually pretty warn. When you go to put the hollow pin back in, you will probably find it difficult to line up. Use a smaller diameter bolt to line it up first. Then without moving the rail try to put in the pin. Don't get frustrated if it takes you several tries. Eventually it will line up.
Use Mike Tangas's excellent suggestion and go and buy a bag of 100 plastic ties at Home Depot. Use them to attach the chains(old and new) to the cam gear. It works great. It keeps the cam from jumping. You can only roll in a few inches at a time. As soon as the chain STARTS to come off the gear, STOP. Keep removing the old ties and replace them with new ones. It only takes about 45 min to an hour for this job. Take your time, so you don't mess up.
Good luck and if you run into trouble come back and ask for help if you need it. That's how I was able to do this myself thanks to this wonderful forum.