The bass bar is now in the final shape. I used the medium finger plane and sandpaper to remove wood in both the vertical and horizontal profiles. The shape is modelled on a couple of old plates that I have lying around, not on any particular classic pattern. I think it's fairly pleasing.
I also cleaned up the edges of the F-holes, removing stray fibers and smoothing out some knife marks. I used a very narrow strip of sandpaper and some machinist's files. I'll probably revisit this before assembling the plate to the ribs.
I was aiming for about 75g, and that's exactly where it's ended up. The scale reads either 74 or 76 grams, depending on air currents and where on the scale I place the plate.