You can try pumping a little bit at the very beginning. This will remove some of the foremilk and possibly avoid the squirting. For my overactive letdown and oversupply, it worked. I tried the baby sitting up position or on top, but my breasts are too big and it was uncomfortable. After a few weeks, things improved with my milk stabilizing and baby getting accustomed to the extra milk.
I think it's different for every woman and every baby. With my first DS, things got better at around 8 weeks. Now, with my second DS, things definitely improved by 6 weeks. He still gets green poops every so often, but the fast let down and a lot of milk don't bother him nearly as much. It will get better for you, take it one day at a time and try some of the suggestions. Before you know it, you'll probably have a fantastic nursing relationship.