i have fairly picky cats, they only like a few kinds of treats(they like the soft ones i think whiskas in thepurple bag the best) but they also only like a few kinds of food.
If i have treats they like, each cat (3) gets 4-5 a day, if i have treats that they dont seem to like, if i mix the non-liked ones into their food they eat them that way.
Their food is also stored into an empty washed tidy cats bucket because it works for me, but when they have treats mixed with food, its normally 9 parts food to 1 part treats ( or 4 3 pound bags of food and 2 packs of cat treats)