Not sure about Redtube but more than likely o for 1000 views. I think I read somewhere its like 1:10,000 for watermarks. You could try being more creative by creating your own ad to insert in the video clip.I personally just use You Tube since you can put a link. I don't even use a watermark I think Its a waste of time, especially if your mass uploading and promoting many sites. I use a scrolling text telling them to click the link, I offer free stuff and I'm promoting porn niches. My conversions are ridiculous.