OG for verbal is a good indicator. Overall verbal score only depends on how good you are doing on all three counts - the SC, the CR and the RC.
Typically i was getting 1-2 out of 10 wrong in RC, 1 out of 7 wrong in CR and 4 out of 10 wrong in SC. But in the actual test ended up with a low percentile of 77....But - in other tests - like the powerprep and the 800 score i used to get consistently abt 41-44 indicating a scaled score of about 84-94 percentile. Again I started the OG very late and did only about 2/3rd of the OG and I regret that decision. OG is the best guide for GMAT Verbal.
I would recommend doing the OG verbal twice atleast to get a percentile of about 90.
Hope this helps.