Looks like the Gator recoil cover?
If not what cover is it?
This has really piqued my interest and I am extremely curious about what exactly you did to get the two to work together because if I am not mistaken, that chase rack direct from ADD shouldn't work with that cover. If you could, please either post here and tag me or PM me all the steps and modifications it took to make this work, as well as pictures of the process if you have it. While this is not something we can recommend it could be something to help me further with someone who is wanting to do what you did.
I look forward to hearing from you!