[cwysong]

Hi Bob,
For grain filler, I recommend Constantines Paste Wood Filler. I get mine in a walnut color. Most of the old radios are walnut and this works well.
http://www.constantines.com/pastewoodfiller.aspx

For lacquer paint, I use the Mohawk brand spray lacquer. You can get toning lacquers in many colors. I always have Perfect Brown, Brown Walnut, Dark Walnut, Universal Walnut and Extra Dark Walnut in my house so I can make just the right toning on radios.
I also use gloss lacquer to finish them off.
http://www.cdmcabinethardware.com/

My feelings on restoring radios is to celebrate the wood, so I always strip them down and try to show the beautiful veneers as they are. If you would like to see some of my work, send me an email and I'll send you some pictures of restored radios.

Hope this helps.
Chris