I used those tubs for a while. I don't know exactly how you are set up, but if you are using a rack system with food hoppers on top of hardware cloth, make sure you put something under the hopper so that the mice (especially the weaners) can reach the food and water. Yes, I know that they will climb upside down on the wire to eat if they have to, but you would too if it was the only way to get food... youd probably rather it be easy to access your food and water. Also, I'd probably go with 1.8. there will still be plenty of room because it is doubtful that all of them will drop at the same time. I keep 1.8 in large litter pans now that I pull pinks only from. As for weaners... 40-50 per tub worked well for me.