The back of this violin has fairly nice figure, which means the grain direction is a mess. To avoid tear-out while using my finger plane, I switched to a toothed-blade. In the morning sun through the east window this morning, it is easy to see the tracks from this blade.
Once the arching is to a point I think is reasonable, I switch to a scraper to clean up all the tooth tracks. A scraper is a thin piece of steel, cut to shape, and then sharpened. I sharpen on one side only. A good edge will raise shavings like a plane or gouge.
With a glancing light, you just keep working until all the 'offending bumps' are gone.