Shirring Tip for Brother Machines

I have been struggling with shirring on my Brother machine and came across a great tip yesterday. I knew that I would have better shirring if I adjusted the bobbin tension but I have a new machine ad didn't want to mess with that tension. I read last night of a lady who bought an extra bobbin case and used the extra case just for shirring. She marked this extra case as well so she would know which case is which. I love this idea and will be using, it did take me awhile though to google and find the part number for my particular machine. Any other suggestions on shirring would be appreciated!!