We are big fans of Stella & Chewy's too. I'm so glad Jackson liked it! I will say I think we pay about $18.99 for a 3 lb bag. So if you decide to feed it more often in the future, it would probably be cheaper to buy the larger bags.
Rory (very active) is 12 lbs and eats 1 1/3 patties for each meal. She does eat kibble sometimes too (1/4 cup of Orijen). Are you sure Jackson would need 5-6 patties per day? It just seems like a lot, so I can see why'd you'd be so hesitant to feed it daily.