I have used the same 50mm clamps as Bill for my old 50mm refractor and as accessory mounting points on the upper legs of the LX90 Meade tripod.
Very effective although I had not considered using 3 of them to support a tray for a battery that may improve stability.
Got mine a bit cheaper from here.
http://www.jdsound.com.au/products/1...0mm-truss.aspx