In reply to IainMunro:
Unfortunately this is something of an individual matter. Some people just need more insulation to stay warm; whether it is Scotland or Nepal. There is no "right" answer. I do not feel the cold a great deal, perhaps rather like you, so my combination may suit you. Only experience can tell.
In practical terms the issue boils down to "what do I do if I am too hot". How can I remove insulation quickly and easily as required or do I just put up with being too warm? You need to be able to adjust things
My solution to this is to regulate my comfort by varying my head and neck wear to vent heat. If I am too hot, which is usually on the descent, I just remove the buff around my neck and unzip my jacket a bit. I might also take my hat off and unzip the top of my soft shell pants. In the morning I just accept that I may be a bit cold at first but I warm up quickly. IME Himalayan climbing is frequently uncomfortable but worth the discomfort.
It is only for a few hours. It is more important that your boots are warm enough. Try not to over-think matters!