According to my endocrinologist the best way to lose weight with PCOS is low GI and to only eat a little bit at a time but often. Apparently our bodies are set up to store every calorie we take in (great if we ever get stranded on the African plains, we're the survivors, not so great in the western world
so you have to trick it and only take in what your body needs in the immediate future for it's essential functions and then it will start to use some of the reserves so you lose weight, also any binge will go straight into stores as fat. It sort of works for me, I lose 0.25lbs a week like that which in comparison to gaining 1lb a week when on 1200 calories a day and gaining 2lb a week on WW and slimming world so I guess it's a success and I'm a regular at the gym for the past 7 years. Unfortunately the only thing that really works for me is TFR which is low GI and also only 450calories a day, not much fun but am just grateful it works.
Also be super careful about doing weights, the hormones we have with PCOS are similar to those in someone taking steroids, you will build muscle faster and bigger than a normal woman and if they get too big you will make the PCOS even worse as it increases the androgen production, if you want to tone muscles, very low weights high repetition is the best for us and put it with lots of cardio. Remember that muscle weighs more than fat too so if you are loosing inches but not weight don't be disheartened, the BMI and weight charts don't always apply to us, getting a set of scales that measure fat and water percentages are much more helpful, get your fat percentage into a healthy range and you are winning. Remember everyone is different too, we all have different hormone levels and different symptoms, my friend has hormone levels that barely mean she has PCOS and she will quite merrily admit she got fat eating too many cakes, I have the worst hormone profile my consultant has ever seen which makes weight loss painfully slow.
Good luck
