"HOW IN THE WORLD DO Y'ALL DETERMINE WHICH TERPENES AND WHAT PERCENTAGE IS IN EACH BUD?"
It's actually quite a scientific process that is handled by third party testing labs. They take samples from a batch grown in the cultivation and run it through their equipment, which then tells them the different chemical compounds present in that sample.
The lab then takes that report and organizes it in a nice Certificate of Analysis (COA), and that's where the consumers and vendors are getting their percentages from.
Here is one of our COAs for Bond Road Kush. There is a lot of information the lab can extract from just a small sample. Check it out!