Are you talking about the brass standoffs used to keep the board off the case? Those all should be the same size. 1/4"? 3/8? Something like that. Those shouldn't be your problem. If you used the retention stuff that came with the 212+, you've done it all right. The best thing to do is to keep the side off, and buy a bigger case.
Yes i'm talking about the standoffs, What other cases are big enough for this 212+?