The salt pushes don't take very long at all. I use 1/4 tsp. celtic Sea Salt in 4-8 oz. of water. Often I will also add 1/2 tsp. of ascorbic acid (slightly more than 2,000 mg). I drink this every time I feel a detox-type reaction such as brain fog or headache. Some people use 1/2 tsp. salt, but this makes me nauseous. I have read that if the first push doesn't clear your symptoms, you can do another in 1/2 hour.
I'm very new to iodine, so I'm still experiencing quite a bit of detox (and maybe not the best person to take advice from, lol). I will often do these salt/C pushes every two hours during the daytime. The symptoms are less for me in the evening for some reason, so I don't do the salt pushes as often.
You might also try a couple of Epsom Salt baths a week. These help me a great deal.