Measuring GROUPS ... make it easy.
I hate trying to measure groups with a caliper & do the math...so I've been using a metal rule for simplicity's sake...
https://i.imgur.com/th6rscV.jpg
https://i.imgur.com/aoBqEvh.jpg
Here's a free program that even us ole'dinosaurs of the keyboard can handle.
https://i.imgur.com/O1QKk1j.jpg
Brought to us by 'F-Class John' on the YouTube...
https://youtu.be/AELFeMMQkow
EDIT...I HATE TO COME BACK AND ADD THIS! Maybe we can find it somewhere else?
https://i.imgur.com/STY3kH0.jpg