If you took Metformin for the purpose of helping to conceive, what dose did you take?

I have PCOS but got pregnant with my son naturally after almost a year of trying. I am trying again but my endocrinologist has prescribed Metformin to help me ovulate. I do ovulate on my own but with long irregular cycles, it's hard to know exactly if/when. I've been taking 1000 mg of Metformin per day and I am pretty sure I ovulate most cycles. My doctor said studies recommend 1500-2000 mg so I am going to increase to 1500. We've been NTNP for about 8 months but now are more serious about trying.

Just curious about others' experiences and if increasing Metformin did make a difference for some people. If we get lucky and conceive, I think I'll have questions for people with similar experiences (and my doctor) about staying on it through pregnancy and breastfeeding but I'll try not to get too ahead of myself.