The simple solution is as follows.
Replace the long wedge bolt with an even longer one that goes through your top cap, the adapter, and threads into the wedge.
Now you can remove or adjust your adapter just by loosening the bolt from the top, just like any old quill stem.
It's a good idea – only trouble in my case at least is that the top cap I wanted to use is one of the Hope ones that has a freakishly large hole and corresponding wide bolt head (see pics above). Not insurmountable but certainly an issue.
The simple solution is as follows.
Replace the long wedge bolt with an even longer one that goes through your top cap, the adapter, and threads into the wedge.
Now you can remove or adjust your adapter just by loosening the bolt from the top, just like any old quill stem.
Any questions?