While losing weight is always a healthy idea, with IIH it's not a guarantee. I have had fantastic luck when I cut out sugars, heavily processed foods, sodas and juices, even dairy. I'm doing the Fast Metabolism Diet (by Hailey Pomeroy). Try to eat natural foods. That will help.
I have had my lp's done under CT fluoroscope guidance and it makes it so much better. My Radiologist insists that her patients lay flat for 45-60 minutes post tap to reduce the chance of developing a leak and low pressure headache. Lastly, I always had to stop taking the Diamox a few days before the tap, to get a true reading. Just as soon as I hit the recovery room I would take a double dose and then get back onto my usual routine to help keep the lower pressure longer.
As you read around this site, you'll see that your journey with IIH is fairly common. Know that you are not alone. We are here to help.