I don't know jack about this stuff but the stage zero dolly platform looks to be a precision piece. If you do not need a perfect plane for the camera to move upon you may be in good shape.
There may be other options vs the uni-strut that will cost a little more but will add precision. Could you splice two of these beam levels together for a more precise travel? There has to be aluminum bar stock out there that is machined for a reasonable price.
Amazon.com: IRWIN Strait-Line 2035105 72-Inch Box Beam Level: Home Improvement