I'm actually using one of these 3M flexible sanding pads for as much as I can.With all those intricate curves are you using a block to sand or just paper?
RKTPWRD recommended it a couple years back, and I've been using one since. It really helps to block the larger areas and contour into the curves at the same time. For the areas it won't work on, I'm carefully doing it with just paper and not trying to "groove" the material with my fingers. I've had to learn the feel and touch per se, but once you learn how the panel or material reacts to the paper it makes it easier.
I see why 3M sandpaper is higher priced, it really does make a difference from the cheaper alternatives. For a production body shop doing insurance repairs...less expensive paper will work just fine due to the sheer amount they go through.