Hey All,
This is something that we have done our best to address with the 15mm REV extrusion.
http://www.revrobotics.com/product/15mm-extrusion/
Our small extrusion uses 3 mm hardware, The small holes in Tetrix are 3.7mm in diameter which is a bit larger than a standard fit (3.3mm( hole for 3mm hardware. In our testing of this adaption, 2 screws placed in any of the small holes along a rail makes a firm connection. We have suspended a 30lb load from the bracket without even a hint of movement (we can test to failure if people want).
This summer we are going to be rolling out a whole bunch of new support brackets, hardware, and accessories specifically designed with FTC in mind.
If you have any questions I am always available.
Thanks,
Greg