Beautiful tree. I do not know how much experience you have with white pine. If it were mine, I think the branches that are very thick should probably be removed, unless you are going to keep one to cut back to in order to create a different top. In time, those thick branches will only get thicker and become even more out of scale with the trunk. Also, removing them will put more energy to the younger, thinner branches. Also, leave stubs, do not cut them flush. Using cut paste is almost a necessity here. If not, they are going to bleed streams down the trunk. It will be quite messy and can get on the rest of the foliage etc.
Once again, I do not know your experience with these, you might already know all this. Very rough material.
Rob