It's time to get out the pruning saw, swallow hard and take the deep breaths. You might want a bottle of Elmer's White glue to seal the fresh cut
wood with.
Decide how tall you want the tree to be allowed to grow, then find those main branches below that height and prune them back first, this will let you get your ladder closer for pruning that central leader to around 3 feet below your preferred height for the tree.
The other option is to trace back on the central leader and when you find the upper most branch you want to keep, cut the central leader off there.
I would leave branches about 3 feet long and probably I would do the same for the central leader.
Redhawk