I'm finally getting around to hanging the dog gate I made last month, and I need your opinions. The gate will be installed like a door in the middle of a hallway, with three 3" hinges and an interior door lockset. I'm planning to attach a frame, like a door jamb, to the wall on each side of the hallway. The jamb is 3/4" thick and 5 3/8" wide. (It's a true 3/4", milled down from thicker stock. Not 5/8" thick 1 x material.) It will only go as high as the gate on each side, and it won't have a horizontal header across the top.
I need this jamb to be very solidly attached to the wall (particularly the side with the hinges). I'm planning to install it on top of the drywall, anchored into a stud. What would you use to attach a 3/4" x 5 3/8" piece of wood to an interior stud wall that would make it sufficient to hang a pretty heavy gate? I don't know the weight of it, but I figure at 66" tall, 35" wide, and 1 1/8" thick, it's only a bit lighter than a frame and panel interior door. I'm thinking along the lines of heavy 4 1/2" or 5" drywall screws, about 8" apart on center. Do you think this would handle the load? Am I running a risk of bowing the wall since it's not framed to hang a door?