well there are massive muslim forums as well, if someone goes on them and posts a link to CEMB, starting a massive thread on let's say gawaher, just posting a link to CEMB and manifesto of CEMB as a new thread, that might bring in some Muslims here to engage with
You cannot post links on gawaher until you have posted 50 threads there. I think the purpose of that rule is to discourage exactly the sort of thing you are trying to do.
But at any rate, I think that the target audience is totally wrong. The kind of Muslims who spend their free time on a Muslim forum are not the kind of people that are susceptible to "open-mindedness", they are mainly die-hards that will not hear reasoned arguments.
You need to focus on a different target audience, the kind of people that are not really that interested in religion, don't know much about it and only say they are "Muslim" to please their parents. Those are the kind of people that would more susceptible to the message.
So a better place to post would be an Iraqi forum about football or a Pakistani forum about cricket, these kinds of forums often have sections for "off topic" threads.
Well, maybe that would be a bit heavy for a sports related forum, but maybe a politics forum would be a good start....