At the top of this first page you'll find a link to some excellent FAQ's, well, some are outdated but one of THE best is the one on How to prevent Cross pollination which I've linked to below.

I've been an SSE member since 1989 and the article I linked to here is far better than anything SSE has written, at least IMO.

I've also posted here several links on NCP, (natural cross pollination), all to say that there are many variables and different folks growing in different areas and different seasons cannot assume that self pollenization is always low.

Hope the link helps,

Carolyn

Here is a link that might be useful: Cross Pollination