PW is their abbreviation for Plain Washer, in other sheets of the TF manual it's called FW...Flat Washer. Flat washer is correct, plain washer is not. This is an example of lack of standardization in the design/drafting dept. at the time. Mil specs and SAE standardization for hardware was just starting to be developed at war time and that would include nomenclature. (AN960 Washer, Flat.... Approved Feb 1942)
Alignment: Stay loose as Bill says and use a round tapered tool thru all pieces to align, like a bridge worker aligns girder rivet holes. In your case, it will allow some sheet metal pieces to slightly "stretch/buckle/twist" into alignment. The holes are called clearance holes. They are, of course, larger than the bolt. All assemblies, of any kind, have clearance holes to allow for hole location tolerances in each piece and the holes will not really be exactly concentric when bolted. Very normal what you are experiencing. Just jiggle, wobble and shake hard as bolt is inserted. You will discover which bolts want to go in first and which last.
