N8622T:
I am installing the sierra TW in my FW as well. I am making the pin at the top removable. If you have the 4 screws at the top Im not sure how to remove it for maintenance if it has problems. I've been warned the air cly is problematic and i will replace mine when it becomes a nuisance but "Ill fly to failure" Screw the mount to the wood support then pull the circlip so the pin can come out then put a small shim at the inside of the door so that it holds the pin in place with the access door in place,
Sparky