I've had students who use double time as an excuse to do everything the hard way, which has had the effect of lowering their score instead of raising it! I would suggest that you still try to focus on efficiency. These questions were designed to be solved quickly. If you spend forever on each question you'll probably just waste time and confuse yourself.

If you have a physical disability that would be improved by standing, moving around, or otherwise getting up from a sitting position, then maybe you can look at the double time as extra time to take breaks. I had a student who had back problems and would feel better standing up and stretching, so that's what she did.

In other words, continue to try to keep to roughly a 12 questions in 25-30 minutes time frame (for quant). What you could do is do 12 questions, then take a ten minute break, doing what you need to do to feel a bit better. Then you could do another 12 questions, take a break, then finish the section. You'll probably still have a half hour left so you could use it as a long break before you do verbal, or else just get to verbal.

I also really recommend practicing the essays so that they come naturally to you. The argument essay in particular is very predictable. If you can put the essays away in only a half hour each (which is the usual time) that'll save a lot of your energy on test day, and help you get in and out without causing too much discomfort. Your scores on the essays *do* matter so don't ignore them -- just practice them. Write one of each kind every week, do what it takes.