Well, I never used an inertial sander, angle drill almost exclusively. I use a firm pad for grits up to 180 or 220, and a medium pad for grits up to 400. If I go over that, then I go with the soft pads. While the soft pads will form into that transition area, they don't have even pressure. The high spots, the bottom of the bowl, and the wall of the bowl will get most of the sanding pressure, and the curve of the transition area gets almost no pressure, so no sanding. With the firm pad, you may have to angle the pad to get it in there, but it keeps the pressure even. You can get a 3 inch pad into a 1 inch radius curve if you angle it properly.
robo hippy