I've made some 3d-printed angle guides for sharpening hollow-ground reed knives. These have significantly improved my knife work since I started using them. The first test items were made in October, after many revisions I have something good enough that anyone who uses hollow ground knives could find this useful.
These guides do not attach to your knife like a sharpening jig does; their only job is to help you measure the angle you are holding the knife at and it's on you to hold the knife steady afterwards. Because of this, they don't interfere with the weight you put on the knife -- one of the problems with sharpening jigs. By doing less these angle guides not only give better results, they are significantly quicker to use.
The angle guides are now available for purchase on my web store here. You get a set of 8 wedges that should cover most hollow-ground knives.