Yes, of course I used the FAQ, but the FAQ doesn't allow time for catching the Guardian. I actually got behind on the FAQ at first because I forgot to match Arcana when I was doing S.Links and that caused me to get behind on a few of them, but then later in the game I realized the guide didn't take advantage of the Fortune Teller to cheese through S.Links, and doing that let me catch back up and get ahead of the guide, then I used the extra days I had at the end to catch the Guardian. Not a super big-deal, since I doubt I'll ever Plat this game. I don't really have a desire to do a NG+ and derp around Mementos for several hours looking for all the treasure demons to complete the compendium.
Still gotta actually beat the game first, I've only just now started Shido's Palace. 75 hours.