Jim's process is as nearly foolproof as you can get—he's a painting pro. There are shortcuts, but you have to have the experience/techincal knowledge to know when or if they will work. That only comes with experience or education or both.
As for baked finishes: Some coatings are formulated to be "baked." These are specialized coatings well beyond the capability of even most professional scale modelers, and they don't apply to plastic or resin models, as those would melt or burn at the required temperatures.
However, cure and cure properties (such as adhesion) of almost any coating can be accelerated and enhanced by application of mild heat, generally less than 120°F. This can be done with a box having holes cut in the top, a lightbulb, and a small fan (optional). Search these forums on "curing" and you should find the necessary info. I use a forced air food dehydrator (~$100). (It pays to buy the right gifts for your significant other… ![Wink [;)]](/emoticons/icon_smile_wink.gif)
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The key factor with acrylics is cleanliness of the substrate. Something that is rarely mentioned is that sanding is not a cleaning process. It needs to be washed and degreased afterwards.
Very highly polished styrene plastic sometimes gives problems with acrylic adhesion, particularly with ModelMaster paints, although it could affect any brand. Wiping down the surface with 90% isopropyl alcohol, denatured alcohol, or ethyl alcohol usually solves this problem.
About all I can say is that I rarely have adhesion problems with acrylics—some brands are more problematic than others, but there isn't one of the major brands that I've used that I haven't been able to make stay where I put it. I never prime with enamels. The only nonacrylic paints I use are artist's oils, Alclad II (rare) and detail metallics. All the methods and techniques I use have been (and undoubtedly will be again) posted in these and other forums. It's not the paint—it's the method.