The fact that it's a "manufactured housing load center" is irrelevant here -- from an electrical point of view, it's no different than any other load center with the same specifications. So, simply follow the two phase instructions, although, for safety's sake, I would have the electric utility pull your meter for you for the duration of the panelboard work as residential panelboards don't separately guard the main breaker terminals, and installing the CTs requires working around them. (It's not like a plastic piece over them'd be expensive...)