How do I scale up to make 10 bars at once?

For 10 bars, you'll need about 1kg of tempered chocolate, 300-400g of pistachio filling, and 100-150g of kataifi. Use a large stainless mixing bowl over a bain-marie for tempering and work quickly to maintain temperature. Have all 10 molds pre-set in a row on your work surface. The main challenge at scale is keeping tempered chocolate at working temperature — use a heat gun or keep the bowl over warm (not hot) water between pours.