Hi,
After reading your post, I've updated ExifToolGUI, so you can (in batch) restore metadata from your original CR2 files into TIF files (see also version info in my homepage).

Now, it doesn't do exactly what you wish... in GUI, source (CR2) and destination (TIF) filenames must be the same -because, filename endings you use (_LR, _X) are specific and may not suit everybody's needs.

Anyway, I'm quite sure, Phil will give you simplest solution for your particular case :-)

Greetings,
Bogdan