@DaikathYes, when the dough is so sticky, dusting with flour doesn't help at all. However, I think 100g water to 150g flour is too much. In my case 50% water ratio would make it sticky enough when pressed with a noodle machine.
I think now I know what is the purpose of alkaline water. In one of my attempts, a few drops of alkaline water made the 50% water ratio dough much less sticky to the degree that it became completely operable and could be pulled evenly -- the most successful I've ever tried.