@wbpeckhamUK based so my only experience is our 24 hour bags, which are all ready to eat or ready to heat. The only thing you tended to make up was porridge. Lots of curry based packs so you’d get scraps over the all day breakfast and stews after a while. I get why dehydrated works for carrying weight (every ounce you save is more rounds or happier knees) but as you say, you need water.