Full Paragon is my usual OT run because I feel like I get the most satisfaction being the pure hero of the trilogy, but I’ve dabbled with being the morally gray Shepard from time to time.
Some things will get the Renegade option, others won’t. ME3 is insanely difficult to balance this on because some Renegade options are typically full blown war criminal status versus just being a badass dude with no care in the world.