If you make this too narrow and don’t make your PCB larger than 17mm diameter you’ll find that the exposed area of GND ring will sometimes disappear during production. If you look carefully at some other drivers you’ll note that they are setup with a thin exposed GND ring plus larger exposed areas where possible.
The A17PZL is a good example actually. Take a look at the OP in that thread. Note that there are narrow GND rings on the top and the bottom. The primary ring on the bottom is skinnier than the ring on the top. The exposed part of one on the bottom completely disappears when OSH Park produces the board! Fortunately the bottom of that board has exposed scallops which are still there. You can see of of that in the 4 pics in the OP.