I think you have a good idea! I started out doing just that at the start of bloom season. But by peak season I stopped. Why? Because I'm too clumsy and kept knocking buds off of plants while trying to get measurements! It just got to be too stressful when so many plants were in flower & bud. Now that peak is over I can do some of the late bloomers but I still need to be careful not to knock off seed pods from crosses I've done. I've already knocked several small pods off & 1 big one that luckily had ripe seeds even though the pod was green.
I have a small yard so my plants are packed close together. If someone has a good way of taking measurements in confined places I'd love to know what it is!