I'm trying my first all grain small batch, mashing in a 3 gal. cooler. For a 5 gal. batch in a larger cooler I normally stir every 15 minutes but for the small batch I think opening the cooler multiple times will drop the temperature too much. What do people think of just shaking up the cooler...

I understand that BIAB mash efficiency can be improved with small mill spacing. I'd like suggestions for best mill spacing and bag microns. Thanks.