It’s possible that you have the wrong cam ring in your mag, or more likely, the wrong contact breaker assembly. The points should open at maximum flux when fully advanced. You can feel this as resistance if you rotate the mag by hand.
The valves are called half compression valves and are supposed to do as they are called! I think most owners leave them disconnected as they seem to be a source of oily smears over the block. I was told many years ago that they help with engine braking but as I have never had mine operational, I can’t confirm if that is true.