I don't have a scooper, but I have a kitchen scale. .06 scoop of ZP is 34g, and 34 grams on my scale was about 90 pieces. So that would be 45 pieces per meal. That does seem like quite a lot. I'd go with Karen's recommendation to start. I feed Gemma 2 tbsp (1/8 cup) of Acana per meal but she is 2.8lbs. Chloe would need more kibble than Gemma, so 2 tbsp of ZP per meal sounds appropriate since you need less ZP than kibble.
By the way, a funny little thing while I was measuring the ZP... Gemma smelled the ZP when I opened the bag and came running into the kitchen. She hates ZP, though. So when I bent down and offered her a piece the look on her face was like "Oh god, no! Not this stuff!"