This project is going to take longer than I thought. I made some progress with grain filling but sanded most of it out to correct two problems - blotching on the sides of the body and tool marks revealed by the stain.
The blotching is probably due to a poor washcoat which consisted of only a couple of light misting passes of Deft aerosol lacquer. I've since learned that the best washcoat is a mixture of 1 part lacquer to 3 parts thinner.
The tool marks were not visible until the grain filler was applied. And even though the body looked perfectly smooth before I started, it quickly became obvious that I should have done a thorough sanding first.
The good new is that these problems can be corrected by sanding and a better washcoat.
Here's the rear of the body with the grain filler applied, but before sanding. Note the contrast with the tremolo route which is not grain filled.
This image shows the blotching that occurred on the sides of the body. After sanding this out, I hope to solve the problem with a better washcoat.
Here is the rear contour tummy tuck. Click on the image to view at full resolution and look closely -- you should be able to see circular tool marks revealed by the filler. These weren't visible before the grain filler was applied. I'll be sanding these out before re-applying the filler.