So, in the car today I listened to the Going Ballistic PodCast with Ryan Cleckner on First Focal Plane Scopes vs Second Focal Plane scopes. He does a great job of explaining what they are, why you would want one or the other and why you wouldn't. Highly recommend listening to this if you don't have a rock solid understanding...
https://www.goingballisticpodcast.com/
Mark
https://www.goingballisticpodcast.com/
Mark