I prefer that all my earrings weigh under 4 grams each. With the clamp on if the earrings are studs. I prefer that all my earrings be from 16mm to 20mm. The problem is the bigger the earring, the more weight. Depending on the design of course.
I always want the gemstone to have an open back. The metal backing will add more weight. If the earrings are pave, I want to see the pave in the back. The lighter the earring, the longer you can wear them and get your money’s worth. Also, your ears will be in better shape after you take your earrings off.
A US dime is 17.91 mm and weighs 2.268 grams. A US nickel weighs 5 grams and is 21.21 mm. I use this as a guide for size and weights.
I have a scale too! I am VERY serious about weights. I have purchased too many pairs that were too heavy. Trust me, your ears will not adjust to the weight. They will hurt and will not look so pretty after you remove your earrings.
My scale is an AWS Digital Pocket Scale. Sometimes I take it with me when I earring shop.