I think the 67 68 should be separated like the 69. There are more than enough differences and information available to legitimately make independent guides. I also believe it does a complete disservice to lump them together, as if there is nothing worth noting about the differences. Will it be easy? No. Consume tens of thousands of hours of time, effort,research, documentation, questions, and rechecking it all again? Yes. Just my opinion, but I’ll be happy to help the project regardless….all you have to do is ask.