Options for refinishing dining chairs?

Hi folks,

I've refinished some french-polished cedar chests but these things are new to me and I wonder if you could advise. (and I have scanned the bible btw).

The chairs are made from a pale timber, coloured walnut. I tried the famous Polish Reviver but the finish is very thin and there isn't much to revive. Even a light sanding with 320 grit took it off in patches and I don't want to strip them right back.

The finish wouldn't dissolve in metho so I guess it's not shellac.

1. Lacquer? If it dissolves in automotive thinners does that confirm lacquer?

2. Can I spirit stain the worn or scatched spots and then respray (assuming lacquer)? (From memory the bible says spirit stain will bleed through lacquer).

3. Can I use my airless gun for this?

4. Or would something like this work: light sanding, a few coats of hard shellac to build the finish and then ending with wax?

Thanks in advance.