Hi Scott,
If you want the pine tree to live, it is not appropriate to use leg spikes to climb it to prune out dead wood. Leg spikes create wounds in any tree; for a pine tree, the smell from these wounds will attract pine bark beetles, which will attack and kill the tree. You can also make it more difficult for the tree to recover from pruning if you don't know how to make proper pruning cuts.
In addition and critical to your safety: Are you sure the tree is in good condition? In your training, did you learn how to identify tree risks and hazards? You must be able to answer this question clearly and with no doubts before you climb. Even tree workers with long years of experience get hurt or killed by taking chances. Please don't.
I would respectfully urge you to learn more from reliable sources (a great many videos on YouTube, etc. are not reliable!) before you attempt to do tree work without much training. The information provided by Jeff Jepson in his books, The Tree Climbers Companion, To Fell a Tree, and Knots at Work is a perfect place to start. The Companion is indispensable and considered the "Bible" for tree workers. The other books are equally valuable. You might also consider our "At Home" (online) Basic Tree Climbing Course.
patty