As long as you have a towel in the tub with the snake, you can raise the water up high enough to almost cover their back.

You want enough towel to have them able to rest their heads or part of their body on it (so they aren't forced to swim to stay above water and stress...) but not so much towel that they just end up sitting on a wet towel. You do need most of their body to be in contact with some water. The water needs to get in between the old skin and new, it will plump up the old skin and that will help pulling it off. So if you see where skin separates, carefully pull some of it away, or roll it off.

You will probably have to do the soak for a good 30 min minimum and STILL have to help with a wet wash clothes.

What I did was stand by the sink after the soak, with luke warm water running and a wet wash clothes. I kept wetting the snake with the wash clothes and then rolling/pulling skin down the body, either with hands or the wash clothes. During all that you have to keep the snake wet, thats where keeping the water running helps..

If you allow the snake to slither around while you do it, they won't stress as much. He will stress SOME, obv., but at this point that skin has to come off...

After you are done with all this, let the baby rest.

Can you post a pic of your setup ? If you use a glass tank it would help to use substrate rather then paper towels. Also, you want to cover the sides and back of the tank with dark paper (stuck on the outside) to give the snake more privacy. Most of the top should be covered too, leaving some uncovered for air exchange.