Integrate the channels separately using ImageIntegration. Then use ChannelCombination to create the color version. Then use BackgroundNeutralization and ColorCalibration to get the balance right.
Georg
PS: if you feel that PI is expensive, then astrophotography may be the wrong hobby for you. How much money do you spend on telescope, mount, camera, lenses, filters, books,... ? However, I share your feelings regarding documentation. Screen the web for web sites such as PixInsight Resources, Warren Kelllers Videos or Harrys Astroshed.