I cannot advice much as I hired Resolute Legal for my appeals. And they won the case.
But we talked about this so much on the forum. Many people shared how they won their CPPD on the reconsideration stage within weeks. Type words like reconsideration and appeal in the Search box and you`ll see hundreds of posts about it.
Also David wrote a great book on how to apply for CPPD. I bought an ebook on Amazon. Here`s the link to his post about the book: Ultimate Guide to CPP Disability Benefits - Need your Help