The cab off procedure is not even ford's it was developed by independants just trying to make things easier on them selves. It has become generally accepted and popular.
As ststed it can be done cab on, the problem is the last 2 bolts on each head near the firewall. There is no room for the last bolt to come out at all. Basically you raise the bolt till it clears the bottom of the head and secure it so it can't drop down and catch on the gasket. I have used zip ties rubber bands even a small piece of hose split to go around the bolt. Comeing out catching on the gasket isn't a big deal but going back on it is not something you want to happen.
The problem with these heads are they are real heavy and you will be working at full arms reach so unless yer young and strong you are gona want help.
Just a lil info for you to think on.