I use the water bath method to cook as well, your time frame seems in range with mine.
Last run i did 2 washes and 2 cooks, was done everything in under 3 hours. longest part for me was coffee filter straining and the last stages of cooking off the final iso very slowly.
I cant help you with the decarbing as i havent ventured into edibles yet, i do remember reading or watching a youtube video tho, that claims if using heat to evap, your decarbing during the cook....i am not sure how accurate that is, but remember seeing it somewhere.