My profession is painting and restoring classic cars. I have found that all base coats are not the same. I am not a big fan of PPG. I like to use RM (Diamont BASF) or Spies Hector products. They cover very well with minimal added weight. PPG will be a lot heavier. I also like to weigh up the primer and all paint products before I apply them to the aircraft. This will help keep you from going overboard when using clearcoats and primers. Another tip is to thin the clear 15% - 20% and this will help spray with minimal orange peal and at the sime time save some weight. Clear coats today are formulated to spray "heavy" to keep them from running when thick coats are applied in the automotive industry. Be careful and do real light coats because it will like to run! Single stage is OK but not real forgiving and in the end you will feel the "paint lines" between the colors and will be heavier when complete. Arch is right if you are mythotical in your application of glass, epoxy, primer and paint it should be about the same as monokote.