i honestly think that prepping is really helpful with Logic Games and Logical Reasoning, and that you should gain a knack with studying. My first diagnostic test,also taken completely cold, was 171, and right now i'm doing the test a day thing leading up to Dec Test, and i get anywhere between 174 and 180. *that*'s consistent, what bothers me/frustrates me is the fact that i jump from 174 to 180 between each test. i'll get a 180-179 and think, alright, i have this down, and then the next test i'll get a bunch more wrong. (i know some of you guys are rolling your eyes right now, but it would be nice to test out at the high range of my potential as opposed to the low range on the real thing, as well as the complete (and unfortunately, needed) boost that an excellent score would give me. just bothers me that i can't consistently score on tests that are supposed to be adjusted for difficulty.. makes Dec 3rd much more scary, especially since i know some people "break" on test day and score lower, sometimes much lower) but, i have to say.. with LR, i've definitely gotten very comfortable with the questions. questions that used to make me think a while like assumption questions, the answer just jumps off the page now, cuz i know exactly what LSAC is looking for after doing so many problems. i usually finish LR section with an average of 6 minutes or so left, after double checking the iffy questions. that is the sort of comfort i think a lot of practicing will get you, eventually, if you haven't reached it yet- and since you said you're still testing around your first score, you probably can improve a lot more.
i don't think any of this new intuition is necessarily something that's going to go away, so if you're not applying this cycle, maybe you do want to put it off and put more time into the test. i think there is a lot of value in going over and redoing tests you've already done, if that's one concern, because going over old Logic Games i've already done has definitely helped me become comfortable with doing them. RC is the only one that is pretty much a crapshoot for me (although there have been times when a certain logic game made me stumble).. sometimes i'll get everything right, sometimes i'm just strapped for time and end up getting a handful wrong.
bah, anyways, that was cathartic for me too. i've got other stuff going on in the afternoon/evenings, but i'm still devoting 2 hrs or so a day to looking at a test. my conclusion is: if you haven't moved past your initial diagnostic score, i do think there is going to be a point when you'll realize you can see through a lot more problems than you did when you approached the test cold. if you haven't reached the point where you know that every wrong question is a question that you'd probably get wrong anyways even with all the knowledge of tricks and reasoning you've taken in, as opposed to immediately going, oh that was really stupid on my part.. then mybe you want to put the test off.
Edited to add: one of the few things that's stuck with me in this mad process (decided kind of late in the game to apply for '06 instead of '07 as planned) is reading somewhere.. possibly on this board, the saying.. if i'd known how important that number [LSAT] was going to be, i'd have studied harder, and started earlier. if this LSAT is going to be such a big determinant of which law school i'm going to end up at, i'm going to give it my best.