Im installing 2 interior doors in a new basement addition. The walls are drywall but have a special layer underneath to promote sound control. The resulting layer of both the soundproofing and the drywall is a bout an inch thick off the stud. I had to shrink both rough openings to fit the doors. Now I need to put in new drywall to cover the gap...

1) How far should I extend the new drywall in relation to the door jam... these were not prehung doors

Thanks,
JM