To follow up on my comments earlier in this thread: After a fair amount of research and experimentation, I decided to use Transtint dyes diluted in alcohol to try and smooth out the blotchy results my friend had attained through his previous efforts at staining. I did not use any conditioner. Before applying the dye, I sealed the purfling with shellac. Once I had completed applying the dye, I scraped the purfling clean and then sealed the entire body with spray shellac. Then I went about my usual approach to wiping on varnish. All things considered, I think the dye worked pretty well. Obviously, it's a hand-rubbed sunburst and will never be confused with a sprayed finish, but that's the look he wanted. I forgot to take before pictures, so I guess you'll just have to trust me when I say this looks quite a bit better than it did before.