Why not use a plastic old work box they a little bit bigger the the metal gem box. I am not a big fan of these and only use them for situations such as this, or to get more cubic inches.
Why wouldn't you want to use these? If you're using romex these boxes are much easier to use than a metal box and clips. I prefer the box made by P&S, but even the crappy Carlon Box is easier to use than a metal box.
[This message has been edited by Electric Eagle (edited 11-07-2004).]