Hi Dave, welcome. All the best in your new venture, hope it isn't too stressful!
Obviously decorating comes down to preparing and applying paint to a multitude of surfaces, so you have your work cut out getting on top of a trade with almost endless variables, but obviously it can be done. Bug the manufacturers of your spray equipment for every drop of info they can share with you. Mainly come to terms with what paints you can spray effectively with your kit.
On the other hand you are streets ahead of the mainstream game in terms of business with your sales background. I was just chatting to a colleague about customer service and the lack of training for the "business side" of decorating.