I leave males with females for up to 3 days max. I have heard of a female striking(male was not hurt) but have never experienced it myself. I think this happens when the female is caught off guard.
I like to see my males at 500-600 grams and females at 1500 grams a least. That is a pretty significant difference. Then I have some females at the 3000 gram mark, so yeah they will be much larger than the boys.