Mature female spiders

OK, so I know a male is mature when he has his final moult and start sperm webbing, but when is a female spider mature? For instance if I want to mate my female GBB in a few years time, how will I know when she is big/old/mature enough to breed?

I have always gone with the guidelines in books, journals and other reading materials. If they say an adult female of a species grows to 5" I will breed her when she is 4-5". I have read that sub-adult females produce a bigger egg sac, stronger young and are better Mums. There is also another guideline I have heard about and that is making sure the females carapace is the same size or larger than the males.

Hope this helps,
Alex

Same as above, if I have confirmed it's a female I will go off the literature at hand or my experience on that sp fully grown size for females and make sure they aren't going to a moult or ideally wait until a fortnight or so after a moult then chuck the male in.

Thanks. I thought that was probably how it was done