Hi Andrew, I think this is still and will become a more relevant topic as menitioned before the quality of lego has changed and not for the better considering the torsos of minifigs to name just one thing. I myself am looking into this and the info here was helpful for me but not complete so the more things we get to know the better, I also want to make the sets with pieces from the right period, mixed bricks make the sets look weird also considering the color eg white old is different from white new you can see it easily and that doesnt look nice when you put a set together.