CM is quite picky. He has to be. What you should do is pretend like you are already in the campaign, and post everywhere else but WO thread, as this thread is not counted. Do that for a couple of weeks or longer, then send an application. 50 posts per weeks is about 7 or 8 per day. You should space it out the whole day too, like post once every hour, at normal "working" time.
Or just look at the spreadsheet and look at the other participants in the campaign, and do what they do, in terms of posting frequency, and where they post. I'm almost sure you can just grab a few, and reply to whatever thread they are in with a full sentence or paragraph, and that should be considered okay.