Well no doubt if appearance ie size weight and cost are considered in identifying a “reference” system, the “best” will likely pretty much have to incorporate many tubes and be quite large heavy and impressive looking.
The competition at the other end of the spectrum could be a tiny unassuming and spartan looking Class D amp from a number of high end makers.
So make sure the test to determine is a blind one. It could be a Samson versus Goliath scenario physically and we all know where any bias based on appearances would exist there. In fact to judge the biggest and most costly tube amps out there anything less than reference would be a major letdown.