So when my new sliding glass door was installed the frame is proud of the drywall by about 1/8" to a max of 3/16". I would normally just put latex caulk in the gap but on this wall you would see this. I was thinking it would be better but a (PITA) to glue a piece of 1/4"x 3/8 flat pine on the back side of the moulding and hand plane it down to fill the gap. I only plan on doing this on the two side pieces of moulding. For the 8 ft piece on the top of the door I will just use shims every couple feet and then caulk it as you can see that edge. Any other suggestions?
Many times I've used a compound square to mark a line 3/16 in from the inside edge of the jamb and used a random orbital sander with 60 grit paper to remove enough material to get the trim to lay flat.