IUI - follicles - MFI - suggestions

So I am cycle day 9 right now. We just did an ultrasound to see how my follicles were looking after 5 days of clomid. So my right ovary has 5 follicles right now, the 3 largest being 12mm, 11mm, and 10mm. My doctor said 5 is a good number and may even be too many if they all grow to 18mm by the time I ovulate. And since they don’t want to run the risk of more than 3 babies, we might have to cancel the IUI this cycle ☹️

My question is: how fast do these follicles grow? I would love to have 3 mature follicles since my husbands count isn’t so great; I’d love to have better odds of at least 1 fertilizing.

Also any suggestions or success stories of IUI working with MFI / low count?