i would hand sand the body down by hand and a D.A sander at low speed with alot of fresh paper on it if have seen were a D.A can screw things up to in the wrong hands start with 80 grit and work up to 120 sand out the low spots with 80 grit you do not want to have loss of hook up on the new paint and you would not want to put any filler over air dry acrylic primer . with all the money you spent on that body i would be very worried that it would come back a lot more screwed up hard to warp it all up by hand sanding