or create an entity (for example a sketched line), dimension the length of this line (dimension which will in fact be driven by geometry), call this dimension in the table.
Then just hide that line.
You can make it shorter by directly creating a dimension in the 3D but according to the users, it is more likely to give off (it is an annotation that will appear at the same time as the other annotations).
I had a system at the time to do what you want to do.
At the beginning I had made a family of parts, and I needed stitches for machining, so I recreated a sketch with the points I had to recover and put dimensions driven by configurations.
By updating each configue, the dimensions piloted in the family of parts had been automatically to updates.
If you're interested in it, I can make a mini tutorial to do it ^_^