I did the notch on my AM. While it is stressful making all the cuts, one thing to keep in mind is you will be adjusting your armor as you learn to troop in it. For me I cut the notch and posterior to match, and removed most of the return on it as well. Makes walking so much easier, when trooping I always seem to be in motion for pictures or high-fives. Doing a couple of long parades also showed the need for comfort.
Check out Seans and AJ's builds, most of your questions have already been answered in there. Both were also good on followup details on changes after basic approval.