Q.How quickly can I increase the amount of water for my tomatoes?
I cut back the amount of water for my tomatoes from 1 hour a day to 45 minutes a day then down to 30 minutes a day due to cracking. The plants are starting to look stressed and I would like to start increasing the amount of water. How many more minutes should I increase per day/week to get back up to the hour they were use to getting?

Certified GKH Gardening Expert
As I am not sure at what rate you are watering, I cannot say for sure, but it sounds like you are watering alot if you are watering that much daily. If the plants are looking water stressed even after being watered, I would check to make sure the water is getting to the roots and also check for wilt diseases.
Tomatoes need about 2-4" of water a week. Put a rain gauge out to collect water in your tomato bed and make sure they are getting that much.
You can also try splitting the watering sessions to even out watering.