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David,

What you have making you look bad is called "plastic shinkage cracking" and the ACI has a detailed paper on it, you can find it at http://www.concrete.org/FAQ/afmviewfaq.asp?faqid=592 this simply is the premature drying of the surface due to a combination of relative humidity, wind, and sun. The surface is hardening while the bottom is still very soft and unable to support the surface allowing it to crack open. You are close to a solution in the finishers aid but you need to find a product called evaporation control, it will be available at most or all concrete supply houses under a name like ConFilm, or Euco-bar, or E-Con or something like that. When about a quart is added to a pump up sprayer full of water and sprayed on freshly bullfloated concrete a "monomolecular film" is created slowing the evaporation of the surface moisture keeping the surface soft until the bottom catches up. Read the ACI paper and take a look at the graph (called an evaporation nomograph) that will help you to measure all three conditions and determine when you need help, let me know if you have any quesitons.