I like magnesium citrate, too. When you get some, consider at first taking the same milligrams you're taking now. Then start increasing it maybe a capsule a day, and hold for a few days, then increase another capsule. Get used to the feel of it so you don't blast past what you can tolerate and regret ever giving it a try :) Tolerance till diarrhea sets in can vary widely, from, say, 400 mg to 1200 mg. Good luck!
I like salt daily, since I feel that it supports my energy. You may have stronger adrenals that get nourished from the salt in your food, and so you'd only need salt for detox that's overwhelming. A consideration is how much water you're drinking. We generally recommend at least half your body weight (in pounds) in ounces of water per day. Sometimes it then becomes helpful to use salt daily so the water goes inside your cells, instead of sloshing about in your head :)
Besides the iodine, my understanding of PCOS is that involves insulin resistance. I believe that losing weight, if needed, eating regular meals, and reducing carb intake should help with that. At the least, if you haven't run across this connection, you might investigate it more. Nutritionist Byron Richards has a series of articles on it. Best wishes!