|I read your section on pruning deciduous trees in|
|Secondary leaders are primarily a problem with deciduous trees, not with evergreens. I think you'll find with time that one of the leaders on your white pine will begin to grow laterally and turn into a limb rather than continue to compete with the other upright leader. Since they would be difficult to reach, why not just wait and watch. I think you'll discover that the tree knows exactly what it's doing; one of the leaders will slow its growth and become a branch.
Best wishes with your landscape!