Hey, guys. Sorry, but I don't have the capabilities to post a picture right now. Here's more of a description of the mod....
The end of the extension arm that slides into the clamp is hexagonal, as is the hole it goes into. This is why it won't rotate perfectly vertical. If you simply file off the corners of the hexagon, making it rounded on the end that inserts into the clamp, it will slide in and rotate completely around to whatever angle you want. And you don't have to worry all that much about how tight the screw is to hold it in. The standard threaded adaptor that comes with the clamp is rounded, and it still holds securely. The slide lock will still hold it in place as long as you don't file it down too far, it'll just rotate more easily. Just secure the screw as tightly as you normally would and it'll hold just fine. Hope that helps. Peace.
Eric