Meanjonathan,
1) I did not specifically focus on the IR section. Given all of the posts out there about the 1st year of IR being a relevant insignifcant factor on your score I chose to work on my quant because I was consistently slow.
2) I completed all of the 12th ed OG problems, the 2nd ed. quant and verbal reviews, all of the MGMAT books, and browsed over the Kaplan 800 book.
3) I completed two of the MGMAT Cat exams, which I thought were awesome, particularly the breakdowns after you complete the test, which is where I spent most of my time studying the IR problems. The MGMAT answers really helped me understand how they tie the data and charts together. My CAT scores were almost identical to how I did on the GMAT, to include the number of problems I did not make it to due to poor timing.
4) I thought the MGMAT questions were pretty spot on, if anything they may have been a bit harder than the actual GMAT IR questions.
I know there's not a lot of takeaways from my post for you to glean from, but the main one would be that all of the prep you are doing for the quant is in parallel to the IR questions and if you can take a focused approach to understanding the question stem and analyzing the chart you will be fine. I don't believe hours of studying graphs etc.. will really help because each question has a completely unique set of data, unlike quant questions which test a relatively small set of math skills in a dizzying amount of ways. There is rarely any calculation in the IR beyond mean, median, and %. You just have to calmly filter through the useless data and keep track of the two or three data points required to make the right calculation. A lot of questions ask you to interpret a graph to find a date, group, median etc.. and then open the data set and make a calculation based on that specific date, group, median or a comparison of two of them. My only real caveat is to make sure you are completely sure of what the X/Y plots are representing. Some of the questions are designed to lure you into interpreting the graph the wrong way and picking the wrong data points. And second, spend enough time with the question stem to ensure you understand it. If they are asking for the % increase in the mean from the two most profitable years, say X and Y, there are a lot of ways to screw that up along the way. It is easy to quickly just look at the graph and calculate the % difference between the largest data points of X and Y. However, the graph may be of the median and year (not the mean and year), and all the data points are in the second tab. By studying the graphs and analyzing the question stem (much like you would pre-work a data sufficiency stem to simplify it prior to solving), the data you need will jump out at you. Last piece of advice, if you get bogged down in the data and lose your way, I wouls stop immediately and make an educated guess and move on. You could easily get lost in all the numbers and spend wayyyy to much time on a question and frustrate yourself into bombing the rest of IR.
Best of luck on your exam.
