I didnt know the only way to get the 19% wa to get an 80 min order. I buy my food from a local bp keeper/breeder that orders i think 150 at a time. So far im happy with 19% never heard of the 23% before though. My lab block are about the same size as you described, maybe a little smaller though. I find that the big rats have an easy time eating and it makes the asf work harder for the food so it reduces waste. I dont see any more dusted food piles anymore.