I Want To Be A Veneer Tree...

 Tree often need pruning to improve quality and form, and one of the first rules you learn is that trees must be looked at from the top down for pruning priorities.  A stag-headed tree is not a candidate to ever be merchantable, unless you can perform remedial measures.  Some trees are so bad that you just cut them off a few inches above the ground so you can grow new sprouts, others can be fixed with duct tape and your pruning shears.

 Evaluate your spreading leaders....

 ...and choose your best bet to make a straight top.

 Wrap several passes of duct tape around the leader you have chosen, and one or more competing leaders in order to pull your choice into a vertical position.  Cut the top of the competitors to take away their dominance.

Clip off any other branches that will hurt the quality of your tree, but try not to remove more than 30% of the crown in one visit.  Come back in a year, cut off the duct tape, and prune the stub back to the main stem.