Very gorgeous!
I personally think you can try two pinkies - or, do a little test. How quickly would you say she eats a pinky? If you don't watch her, try having a look next time (and have 2 pinkies prepared just in case). If she gobbles it up no problem and it seems quick to you, she's probably good for another one. Anther sign is if they continue looking for food afterwards... although some do this regardless
Or, to be cautious, you could wait until you have a scale. I got a nice digital kitchen scale from an army surplus store for $8!