I spent a little time getting the remaining finish out of the cavities, then did some block sanding to get the wood ready for sanding sealer.
I was planning on using just sanding sealer, but after two coats, there was a lot of grain texture remaining, so I decided to try grain filler, a thick oil base paste that fills the low spots in the grain and gets you to a flat surface faster.
What I discovered was it would have been better to use the grain filler on the raw wood, then sanding sealer after that.
The final step was to use a shellac sealer to cover the body to prevent the lacquer from penetrating the sanding sealer. Back in the day of painting autos with lacquer, you would have to spray a sealer before finish coating or all your sanding scratches would magically appear when you got a few layers of paint applied.
I used a few coats of clear lacquer over the shellac to clear up any remaining grain.
You want the body to be glass smooth before you start laying down the color.
Here is the body before wet sanding the clear.