Alternative to the Bind-It-All Space Bar
 

I saw this in another thread but it doesn't seem to be active any more, so I'll ask it again.

The alternative to the Bind-It-All Space bar that was posted was to cut a sliver of Fun Foam. This sounds like a fabulous idea, but I'm not sure how wide to cut my sliver, I guess because I'm not sure which way it will be inserted.

Can anyone give me more details, please?