I save the leftovers to stick in the birdie bread too, all other waste goes to the wild birds in my garden, who gobble it all up with gusto
I used to do that all the time as well! Jack would always have loads of pellet dust in his dish, so I saved it, storing it in the fridge. Then once I had a cup, I would use the pellet dust instead of flour in my birdie bread
In regards to the question, typically I suggest a pellet size smaller then needed to most bird owners that come to the pet store where I work. The reason being, I have found with my own birds that when the pellets are too big , there is more waste and more pellet pieces tossed around the house lol