Many years ago I had an in-depth discussion with a Jaime Garde who was the chassis tester for RMC, when Mike Moyland owned the Company.
It seems in those days not only did RMC build cobra kits but were also the state approved chassis test facility. Their job included testing stretched limo and all manner of chassis that were modified/built to go on WA roads.
A beaming test went like this:
A rolling chassis/car was built complete with motor, transmission and all suspension adjusted to ride hight. Door intrusion beams, hinges and latches were also to be fitted
All wheels were then removed.
The coil over/shock/spring components were removed and solid struts installed reflecting the correct ride height.
Hub plates were then bolted to the wheel hubs and fixed to the test platform.
To test each corner, the hub plate was detached from the platform and a measurable hydraulic force applied perpendicular to the hub flange. A dial indicator measured the deflection.
He claimed the MK1 RMC chassis failed miserably and hence the redesign to the Mk2 double rail.
That redesign was at the request of a Rick Percival and Connor Craig who were then attempting to market the RMC in Queensland. The Qld Dept. of Transport wanted proof of beam testing.
That's the way I remember it but it was a longgggg time ago.