Overnight I keep the hot water in the bottles in an insulated bag and the forumla in a dispenser and add when ds wakes. I also put an extra bottle of super hot water in the bag and that keeps the bottles warm. If you try it over a few nights you would work out the right temps to start with. I figure it is just like going out for a day. I do all this after the 11pm feed and the 3am feeds is covered. Good luck.