I remember that, president Carter was a real forward thinker. Too bad the energy glut right after lulled people back to sleep.
If the glycol is still slushing at 50 50 it may be breaking down, not sure what eventually happens to it, but it has a certain life expectancy. Might do to test the freeze point, 50 50 should be minus 40.
The concentrators are pretty attractive. The bigger the better for efficiency, but 6 x 6 ft should still give practical results. I like that they are just simple focused mirror elements. The tracker is the big issue as precise alignment is necessary, an event timer with a movement every 5 minutes should do fine for that. MEN detailed a thermal tracker years ago, it would win for simplicity and energy efficiency. Although a gear reduced shaded pole rotissery motor could point a balanced array.