Cervantes, your really great article on dpreview and the discussion here convinced me that canonrumors is not only a forum for stealthy Canon bashers but still can be a good source for Canon users.
I'd just like to add a little warning for those few readers who still use a vintage EF 500mm F/4.5 like me: do NOT try to set "Lens drive when AF impossible: OFF". First, your 5D3 won't let you do that with this lens attached. But if you switched your camera off and then on again, strangely the camera accepts this setting but the lens' AF/MF drive is completely dead. Fortunately if this happens the 5D3 accepts resetting "Lens drive when AF impossible: ON". I think the reason for this strange behavior is the vintage full drive-by-wire focusing system of this lens.
Any other settings described in your article work perfectly, Cervantes, I found about the same settings to be most useful e.g. for birding.