An apparatus includes a body with a first body portion, a second body portion opposed from the first body portion, and a connecting portion that couples a proximal end of the first body portion with a proximal end of the second body portion. The connecting portion is configured to permit the first and second body portions to move toward and away from one another between a plurality of angular orientations. The first and second body portions define a distally opening angle. A first adjunct element and a second adjunct element are disposed on outwardly facing surfaces of the first and second body portions. The first and second body portions may be fixed in each of the angular orientations and may simultaneously apply the first and second adjunct elements to first and second jaws, respectively, of a surgical stapler end effector.