Indeed, that is a good choice. There is a good kit market for this scale but limited ready to run options. If you were entering this market, it would seem prudent to operate at a scale with limited competition. Hence why I suggested G1. 10 years ago, RTR O gauge at an "economical" price was unheard of. There is no reason why G1 couldnt progress the same way, apart from space constraints of layouts, hence why small sized prototypes would need to be chosen. Your choice of 7mm NG helps immensely with the space problems though.