This pic begins the series about planishing hammers. It demonstrates the surface that will be smoothed in future pics. Gene refers to them as Walnuts. Gene wanted a compound radiused surface. He needed to stretch the metal. He did that with a shot bag and a HDPE hammer. When you planish, you will smooth out the surface between the "walnuts", by a combination of shrinking the walnut and stretching the surrounding area.
By now, you've seen a ton of pics about the vixen file. The proper way to use it is, by going across the surface diagonally. Straight across will leaves ridges, or railroad tracks, so to speak. To level, hit the area from different directions.
Rather than bore you with successive pics, the next step would be to sand with 80 grit, then work down to 220. A couple coats of primer and your done.
Now is a good time to recheck yourself for any metal that you moved with the torch. The lead is flexible enough for some light metalworking. You might have warped some metal when applying the lead! Double check as your filing, and adjust as required.