DISCLAIMER: I am no lawyer. And I am not an agent. So I am not one to give legal advice. This counts more as common sense so keep that in mind. I want to say this about contracts, and it’s learned from experience:
No deal is always better than a bad deal.
Recently, I’ve spent a lot of time negotiating contracts, and it’s got me thinking back ten years to when I first started out as a writer. For the first two or three years especially, it seemed like I was never going to get a sale, let alone a pro sale. And that made me feel like my legitimacy as a writer was very much in question. So one day, when a deal came along that paid pro rates and offered me that opportunity, I faced a real delimma. See, they were paying me ten cents per word. And that was at a time when 6 cents per word was the pro standard, so this was great pay. But in exchange they wanted my copyright and along with it the right to rewrite me however they chose without my involvement if they decided to do so.