Personally I would put all that unused land toward industrial sites. Set turrets 90% troops and spies at 5% and get rid of all those tanks they're laying heavy on your upkeep, sell your max cap of turrets on the private market twice a day, and buy what you need from there. If you don't get nabbed for being land fat your a lucky duck. You should have more money to know what to do with in a few days and you'll never be low on defenses. If you feel the need to make a retaliation just buy a few hundred thousand jets, or don't sweat it and move forward. You can spend extra turns on industrial research and when you have an abundance of that sell sell sell. If your expenses get out of hand put about 400 sites on both residential and enterprise, and if you don't like your food shortages put another 400 on farms.

Sometimes you just have to play a few times, even the best formulated plans, and well calculated efficiency isn't always enough, timing on the market and using your turns wisely can pay off more than a perfect adherence to formulas and ratios. Knowing game dynamics is good, don't get me wrong, but reaching number one can be done numerous ways, not the least of which is by the help of some friends.