Joe Fuss, owner of Ragg's... to Riches?, recommends the following for painting his wood structure kits.
Do not use straight acrylic paints; they are too thick. He does recommend applying a very light coat of primer, so that all the painted parts will wind up looking the same (unprimed wood can lead to different color shades when the final paint coat dries).
These are instructions he includes with each of his structure kits. For a solvent-based paint, he recommends using Sherwin-Williams "All Surface Enamel, Ultra Deep Base" (one quart #A11T00214 for each color), with the following mixes:
He notes that Sherwin-Williams recommends either Paint Thinner (Mineral Spirits) or Xylene for thinning and clean-up. He finds that Xylene seems to work better, especially for cleaning an airbrush (he uses the same when using Floquil paints). He has found thinning the Sherwin-Williams products with 3 parts paint to 1 part thinner works best. These paints are labeled as a "satin" finish and the parts will dry with a slight sheen. Overspray the parts with Testors' Dull-Cote to eliminate all sheen.
He says that Sherwin-Williams' smallest size is 1 quart, so you will have a life-time supply. Keep an eye out of their sales, as they may offer the paints at about $15 per quart.
For those who cannot or don't want to use solvent-based paints, one modeler noted that he has successfully used the Vallejo paints product line, thinning them down and using an airbrush to actually apply the paint. He has also used Delta Ceramcoat in a similar manner with success, using Liquitex Flo Aid to keep the airbrush from clogging. For rolling stock, he has found that Delta makes a black called "Charcoal Gris" which is a perfect match to Floquil's "Weathered Black".