This is a perfect case for using the cheap old Lee Safety Scale.
You zero the scale, set the weight, lock the vernier window with the pin and your scale is all set. After dialing and locking in your powder drop, you simply check every 10th round or so by dropping it into the pan. The slider cannot move so all you need to do is to see that the needle is close to or on the line.
I know there are some who are "all thumbs" or cannot clearly see anything closer than 6', but this scale only needs to be adjusted carefully once and you don't even need to be weighing anything, just set the window and lock the pin. After that, it's pretty easy to see whether the indicator needle is pointing at the line or not.
You zero the scale, set the weight, lock the vernier window with the pin and your scale is all set. After dialing and locking in your powder drop, you simply check every 10th round or so by dropping it into the pan. The slider cannot move so all you need to do is to see that the needle is close to or on the line.
I know there are some who are "all thumbs" or cannot clearly see anything closer than 6', but this scale only needs to be adjusted carefully once and you don't even need to be weighing anything, just set the window and lock the pin. After that, it's pretty easy to see whether the indicator needle is pointing at the line or not.