A click is a unit of measure.
Bad news it can be 1/4" at 100 yards, 0.36" at 100 yards or 1000 meters!
Best thing you can do without a chrono is put it on at 100. Shoot it at 200 and measure the drop. Put information in a ballistics calculator and change velocity until it matches.
It will give you the rest. I did that for a long time.