The chest mount I describe in the post with the link Wreckdiver was so nice to provide is only one set up. There are other pics of the different chest mounts others have come up with.
The chest mount is great as it takes all the dead weight off the arm unlike a straight shaft and cuts water resistance too. The only thing you need to watch out for is to make sure you get all the wire in the trunk before slamming the trunk. It can happen when you tired.
Good Luck,
Sandman