Systematic approach to learning opening/endgame theory? Some relevant information: I've been playing chess for 4 years, and for 3 in tournaments, although I've only played in about 10 tournaments so far (3 big ones, like the Pan Ams and Chicago Open). My current rating is 1650 UCSF, and my chesstempo rating is 2100, if that is relevant. I'm fairly strong at tactics (and getting away with unsound sacrifices), and decent at positional play (I can recognize the value of controlling dark/light squares, using/creating outposts, securing open files, removing defenders, playing with a space advantage etc). 

The Problem: Theory. Although I play the King's Gambit as white, and the Alekhine's Defence/Grunfeld as black, all highly theoretical openings, I don't actually know theory beyond, say 5-8 moves at best. I'm a highly tactical player, so I just seek to create complications from the opening, and end up having a decisive game in the middlegame due to the ensuing fireworks. I've reached the endgame exactly twice so far (out of ~70 games, in tournaments), and hence have very little experience in them. But recently, I've been getting outplayed in the openings, and have decided that its time to man up and learn opening/endgame theory. Since its an arduous task, I request to you, wiser, more experienced players to give me advice on how to fight this monster. Where should I start? Is learning theory just rote memorization? How much is enough (certainly, 8 moves of theory won't do in the King's Gambit or Grunfeld, but may suffice in the Alekhine)? 

I've tried to read two books on chess so far: Silman's "Reassess Your Chess", and Taylor's "Alekhine Alert!". While both are highly interesting, I lose patience when they spit out a 50-move continuation after showing an interesting position, and due to not having a board around, I slam the book shut. Do you guys know of any books that don't do that/other resources to help learn theory in an entertaining way?

P.S. I'm very scared of the French and the English because they are highly theoretical, and score very badly against them because I keep trying odd responses (I play the KIA against the French to avoid having my d4 pawn targeted, but get crushed on the queenside anyway, and try the Dutch defence against the English to not lose due to boredom, but lose due to inferior pawn structure (mainly) anyway).
I will preface this by saying that I'm a 2150 USCF player who has had the same issues that you are struggling with in the past. What I'm about to tell you comes straight from my own experiences playing chess all these years.

Don't study or memorize any theory straight up. I find it difficult to retain information like that and the potential for it to be used is minimal. The best way to learn theory is to first forget about it, and instead play games with that opening. Then after the game, when you are at home look up the theory for whatever variation you are playing and learn the theory AFTER you've played a tournament game with it. This usually consists of finding books related to the opening you've played, poring quickly through some GM games in the same line, and annotating the game you just played.

The amount of theory you need to know is enough that you
1) won't fall into any opening traps and
2) that you have a general sense of how to play your position once you are out of book. 

There isn't a set number of moves you need to memorize, but these two criteria are questions you should ask yourself if you think the amount of theory you know in the opening is insufficient.

You might say that you are scared that if you don't know the theory, you might lose straight out of the opening. From my experience, you will win if you are the better player no matter what opening you play, and you will lose if you are the worse player even if you are armed with loads of theory. You say yourself that you feel that these other players outplay you out of the opening, but honestly, I have a feeling that they would've outplayed you no matter what the opening choice. Upping your entire game, and analyzing what you could have done better in the resultant opening and middlegame positions is far more important than a few temporary setbacks in tournament play.