If the holes are EXACT to the old PG, then it can only be the fit at the neck causing you grief. You did say the tech forced it on at the pocket. The tech is not very good if he didn't help you line it up!!! Never go back there!

The only remedy is filing the neck pocket of the PG until it lines up. It's so easy to do, just take your time with a 1" fine Metal working file, continuously checking the fit. File material away on the SAME side of the pocket to the direction you want the PG to move. Think of it as a pivot from the bottom of the neckpocket. File from the bottom of the pocket gently out towards the tip of the pocket, light pressure. Maybe three strokes and try the fit. Repeat as needed. Smooth out with fine sandpaper.
Because the pivot point of the PG adjustment is at the pocket Tiny amounts of material will make a huge move the farther away from the pocket the screwhole is. FOLLOW? Once you are done, you will not be able to see ant huge gaps at the PG pocket. If,as you said, you can force the screws in at an angle, you don't have much material to remove; a couple hairs will do it, HONEST!
This is easy and you will be happy that you did it yourself! I wouldn't take my dog for a bath to that tech.