How should rice-crust consistency be evaluated when buying a rotating clay-pot cooker?

To judge rice-crust consistency, cook the same recipe with fixed rice-to-water ratio, heat setting and reduction time at every burner position, then measure crust thickness and compare browning, since uneven burner heat shows up directly in crust colour and depth. Sample both outer and centre positions, and on units built for continuous service run a midday and evening peak batch to see when crusts thin or pale. Put the acceptable thickness range and colour tolerance into the acceptance terms and recheck on delivery.