I think it really depends on you and how your body acclimates. Have you done this before? Have you needed more than a day for your body to adjust in the past?
The best I've felt on the trail to Whitney was after I spent three days and two nights at the Portal camping with my family before I left. The buddy that came with me for the entire camping trip and the hike got sick at Trail Crest despite the three days of camping at the Portal. I also have tried driving from about 1000 ft. to the Portal and leaving straight away and wound up with AMS. But I have friends that can spend a night at the Portal and be fine even though they live barely above sea level.
