On 5/12/2013 10:15 AM, dpb wrote: ...
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Or, you could simply use a horizontal support fastened to the two uprights w/ "enough beef" to support the load--tubasix would do nicely and still be thinner than it appears your verticals are now...
I just went w/ the solid center support (or you could replicate the ends in the middle as well) as it's simple and adds both vertical support as well as racking by forming a truss member that is pretty much lacking anywhere else at all (as others have also noted).