those devices were called the pre-val sprayer they were poor at best ( I used to sell them)they worked good enough if you had the method dialed in to perfection,far from user friendly, you can spray latex paint through a airbrush if needed, I have done several models with WB paint using a airbrush.

its all in the proper thinning,air pressure, and tecnique.

for med size jobs a touch up gun can be used there available from home depot or lowes, I have one made by Huskey, it cost about 35$ and is powered by a regular compressor, nail gun type is fine, I also have the fittings for my airbrush as well I just dial the pressure down for spraying.

thinning latex house paint can be done with,strait water,denatured alcohol( for rapid drying) which tends to burn(dulls) the finish a bit unless diluted with water, or window washer fluid works well.
WB paint needs at least 25-50% thinning to get it to spray properly depending on the material, there all different and depend on the quality, if you are spraying a model then get the best brand you can, high quality paints tend to have the finest grind rates, the raw materials are ground down to a very fine level, this also helps it move through the machine easaly, whatever type.

poor quality paints have a courser texture and will clog alot easyer,something to think about when chosing a material.

hobby paints that are water clean up like model master are a very high quality but are expensive.

the water based paints I use primarally is www.warbirdcolors.com paints, there catalized urathanes, water clean up, and when the catalyst is added at 8 drops per oz its nitro proof to 15% I thin with pure water at about 35%

most of my painted models are WWII type but the paints from WBC come in many colors.

keep in mind latex paint is not nitro proof and needs to be clear coated with something that is,latex is gasoline proof when fully dry, but I clear coat it any way as well to cover any sanding marks or scratches.