Hi ankitprad.
I'm not 100 percent sure what you mean by strategic guessing. If you mean guessing on some questions that you find particularly challenging, then your strategy may make sense. On the other hand, guessing on random questions just to catch up with the clock doesn't work out, because you may guess on questions that aren't very difficult. If you guess on, for instance, a Medium level question and miss it, the test will take that miss as a signal that your skills aren't strong.
Regarding timing on SC questions, actually, harder SC questions can easily take close to, or even longer than, two minutes. So, it doesn't make sense to expect to get through every SC question in 1:30 or under.
Regarding verbal timing in general, to speed up, you have to become more skilled at seeing what's going on in the questions. The better you are at seeing what's going on, the faster you'll see it, and the faster you'll answer questions.
To become better at seeing what's going on, you could do a lot of UNTIMED practice involving analyzing all five choices of question after question to define exactly what makes the incorrect choices incorrect and the correct answers correct. By doing all that analysis, you'll develop an eye for the issues and learn to do the analysis rather quickly.