My DS is 13 months and we are working on getting down to a before-bed nurse only. I've been removing a feeding ever couple weeks (you can do it faster, if you want). DS nurses mroe to eat, not so much for comfort. That sauid,. there are times he does want to nurse for comfort. If we're home, I will sometimes let him, if we're out, then usually not (I try to be consistent to avoid confusion).
It has been helpful for me to have his blanket and a snack/drink on hand. This way, when he wants to nurse, I can give him one or all of those things to help comfort him.
I have read to start with midday nursing first, then remove morning, then night. I think this is based on how tired the child might be and how easily they miight be distracted by soemthing else. Maybe this schedule will help.
As to the cold turkey--up to you. I would consider, however, how much pain you might be in, and how upset your son might be with a sudden stop, and if that's worth it.