I'm afraid this question might be too specific, but just thought I'd give it a shot since everyone is so helpful. It's 1:33 am so no, I haven't called tech support at HQ yet! My question is this: I ordered the casters for my frame which is set at 12'. They sent 4. That means 2 on each end. What about the middle!? That seems like a long distance to not have support. Thanks in advance to anyone that owns this set up and can help me .... at 1:35 am!!