Andre, I can relate to the issue of scale GPs and RSs. I bought a Railking semi-scale diesel when I first got into O gauge 3-rail. I don't even remember what it was now, but I soon realized I was not into shrunk down semi-scale. I do have a couple Railking diesels, but they are scale.
I'm glad you have good support from your wife and long time friend. My wife is a great support to me! Yes, I agree, you need to keep evaluating this and not make any purchases yet until you get a good handle on it. On the other hand, I know you realize you don't want to get into analysis paralysis either. I tend to be the same way!