Tripod Collar for Macro Rig

I tried posting this in the Lens section, but couldn't get any interest. I currently am shooting macro at 7.5x with my T3i connected to a full set of cheap Fotodiox extension tubes (Like these), a 55-250 IS II at 250mm, f/11 and MFD with a 50mm f/1.8 reversed set to f/8. The problem is that I cannot mount this setup on my macro rails and tripod because it is so front heavy when using the camera mount. The balance point seems to be on the extension tubes. My question being does anyone know if there is a tripod collar that is a fairly close fit to the size of the extension tubes so I can mount the lens contraption with better balance?

I have been in the same boat. There are 2 options to my knowledge one is this device which also requires a dovetail plate http://www.ebay.com …_trksid=p3984.m​1423.l2649 the otehr is this which seems like it would make focusing difficult http://photo.net …gital-camera-forum/00CYb4

i think you need this dovetail rail with the first ebay item http://www.ebay.com …ain_0&hash=item​2eb99948eb