Bill, I’ll throw one more idea at you. You can fill and stain and sand at the same time by wet sanding. Flood the piece with dark walnut or black walnut watco, let it soak in for about 30 minutes (keeping it wet) and then wipe it off. About every hour or so check it and wipe it...you will likely notice some of the finish will seep out over the coarse of the next few hours (I usually start this in the morning). Let it dry for a couple of days.

Flood it again and this time wet sand it with 400 grit wet/dry sand paper. It will form a slurry that will fill the pores. Let it sit about 15 minutes, then gently wipe it down. Check every hour or so again and wipe if needed, then let dry a few days.

If you see the pores need more filling, repeat the process.

Let it dry for at least a week, then top coat it.

It’s one of my favorite ways to finish...but it is a long process.