How do you adjust Silvretta 400 - need a special wrench?

I got these from ebay, and the two bindings are not adjusted the same. I've tinkered but can't see how to loosen the clamps that hold the binding at the detents.

I found a scan of a 400 Instructions for Mounting and Use that refers to an adjustment wrench, which I don't have. Don't even know what it would look like...

https://i.ebayimg.com/images/g/OGcAAOSwcK9hoUxd/s-l1600.jpg

There is a bar that pivots around the adjustment screw (11b in the image). This holds the retainers (7) in place. Turn the bar slightly, release the retainers, and slide to the appropriate notch (6). Then re-engage the bar.

There is no bar on the 400. 

I don't remember the specifics, but I adjusted a set in the woods once. No special tools needed, probably just a screwdriver.

On the older ones they had round brass colored thingys holding the teeth into the notches on the bar frame. Pop them off with a screwdriver and adjust to size and put the thingys back on.

Jack Carbon wrote:

On the older ones they had round brass colored thingys holding the teeth into the notches on the bar frame. Pop them off with a screwdriver and adjust to size and put the thingys back on.

That's how the 400 is. I could see that it was possible to pop those off but I was concerned about stretching or breaking them and then having no way to hold them shut. I'll give it a try.