Anderson, Good idea. I keep a data base on all my customers. Started from the beginning. I have over 7000 entries at this point . I keep model, makes, any quirky customer notes. I always get the man, woman and kids name. When someone calls me, I look up their wifes name and can address them by name if they call. It is sometimes the little things that will get people to like and trust you.
As for moonlighting, if your working for a company why mention it at all? Even if it is allowed, I wouldn't say anything if it was me. When your ready to go on your own, then tell them not before and I wouldn't mention it to either customers or your bosses. or fellow employees.