Mentioned web site provided me very fist information I got when I started with Honda SOHC - that time (Jan 2018) I found ad offering 750 K7 (USA import) low miles all original. Based on photos I was interested, but as I had to drive ~400km to see it, I started to look for some info to verify based on photo if bike was really all original.
http://honda750expert.com/ site I found first and helped me after several hours to understand all details that makes K7 original. And next day I bought the bike and my SOHC story started
Just later I found sohc4.net and this forum here
But generally agree that this particular site is not easy to read and it practically contain only US bikes info.