Reducing the amount of time the women have to comment may mean that no women comment at all.

I emphasised a word in my original proposal, just to avoid a possible misunderstanding. Women would have all the time to comment. Only the first day or two it would be exclusive time, and later the discussion would be open to everyone.

I agree that if we already don't have enough women here, they may be unable to make a longer-than-epsilon discussion. But I feel bad about asking someone specifically to comment on a post. I know I probably wouldn't like to be asked to comment on a topic which may not interest me naturally, just because I happen to have some trait.

what conversational differences will you look for and how will you know that you found them?

A lack (or just less) of whatever women complain about in articles like this. Whether the complaints are about form or content. During the protected time period those things should not happen at all. (Unless some complaining women are wrong about the cause of their complaint. We could possibly find out that e.g. rationalist women do also naturally produce "less warm" discussions than is usual for women discussing outside LW.) And later, the discussion should already be primed. (I know it does not stop anyone from introducing e.g. the topic of PUA. But even if that happens, the discussion will already have a lot of threads without this topic, so this topic is unlikely to become dominant in the discussion.)