In my opinion, I think the CR on the GMAT and the questions on the official guide are sufficient for studying on CR.

I have taken the LSAT before and the logical reasoning on the test involves passages that are less straightforward and include question types that you will not see on the GMAT such as parallel reasoning or role of argument (and these almost involve a flaw).

To master the LSAT with a score above 160, you will have to knock down the sufficient (If) vs. necessary (then) condition on the logical reasoning portion of the test, ice cold. Many questions will test your ability to get this down. GMAT questions generally won't ever require you to consider such scenarios, even at harder levels of difficulty.

Besides, you will only get 11-13 of these anyway for the GMAT out of 41 questions in verbal, or 78 when including quant. On the LSAT, you get 51-52 of 100 total questions on the test. Because 51-52% of the LSAT is logical reasoning, so the testmakers will inevitably make problems that are much more difficult and convoluted to a point where such questions will not appear on the GMAT, even if you score in the mid 40's on verbal.

Also, I wouldn't suggest using LSAT reading comprehension as additional GMAT prep material. The passages are much longer than what you will find on the GMAT, and you will also have to understand sufficient vs. necessary conditions.

If there is a part in the verbal section you should study more, it's sentence corrections which show up more than other question types, but even then it's not much more than a third of all questions. You will get 15 at the very most out of 41.