FLG vs OCG

binatical

is the FLG enough to pass all three tests or do you need both books?

OctalDump

OCG is more comprehensive, including what FLG treats as 'assumed' knowledge, it's a bit drier. The FLG is more like a course text, taking you through what you need to know in a fairly accessible way and integrates well with the Net Acad course and the Lab Guides.

Personally, I'd recommend using the FLG and lab manuals as your main study tool, going through both from beginning to end, and supplement that with whatever you feel you need for where you might feel you need/want to know more or want a different perspective. The Chris Bryant videos on Udemy are a pretty good supplement. You might also use the OCG more as a reference for particular topics.