I would imagine that running the wheel to be dressed slow, and the dressing device fast, would be a faster way to dress. Ordinary abrasive cloth flapwheels I simply dress on a bench grinder, both devices turning in opposite directions. Typically I'd run the die grinder slowly while the bench grinder runs its normal speed.
The wheels you have described are very much larger though. Perhaps if you can rig a method to turn the flapwheel at a moderate rpm, you could cut the shape into it with a handheld angle grinder and a thin edge grit disk. You might have to kind of notch the cuts as if felling a tree with an ax.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)