Currently we have an app with a number of features that fit well into a tab navigation bar below the action bar. Because of the vision of having more features in the future, business guys want to have just everything in a "Sliding Menu".
I'm quite aware of the problem of sliding menus and the low level of engagement of users for those "hidden features". I suggest keeping features into the tab navigation bar like now and in the feature probably have a sliding menu for the less frequently use features.
Finally, because they are still unsure about what's better, I suggested A/B testing. So, how long should we keep each navigation approach live to have a strong data to compare? The time for any A/B testing is the same of it changes depending of the nature of what we are testing?