You can use a methodology from soil testing for this that doesn't require extra gear. Sieves (like with soil texturing) will give you a faster more accurate answer. Here it is:
Get a narrow glass jar. Fill it a little way with ground coffee. Fill with water. Shake. Set on shelf and wait a few hours up to a day.
The larger pieces will settle first and the finer settle last. You can see the sorting of them through the glass. If you use consistent amounts of coffee and the same container, you can measure depth of layers. I.e. this grinder makes .5cm of fines to 3cm of ideal to .2cm of too large.
Bonus is you can use this method for making cold brew, so you don't waste the coffee or water.